“feasible and prudent” heritage...

ACT Land Development

Agency

Northbourne Housing Precinct Dickson and Lyneham, ACT

“Feasible and Prudent” Heritage Alternatives

30 September 2014

Northbourne Housing Precinct, ACT 26 September 2014 “Prudent and Feasible” Heritage Alternatives Summary Report

Graham Brooks and Associates Pty Ltd

Graham Brooks & Associates PTY LTD Incorporated in NSW

Architects, Planners & Heritage Consultants 71 York St, Level 1

Sydney 2000 Australia Tel: (61) 2 9299 8600 Fax: (61) 2 9299 8711

Email: [email protected] www.gbaheritage.com ABN: 56 073 802 730

ACN: 073 802 730 Nominated Architect: Graham Leslie Brooks

NSW Architects Registration: 3836 Issue Description Date Issued By

A Draft for LDA Review 18 September 2014 GB B Final Draft for LDA Review 25 September 2014 GB

C Final for Submission 26 September 2014 GB



Table of Contents

Executive Summary 4

1.0 Introduction and Background 6 1.1 Introduction 1.2 The Three Conservation and Upgrading Options 1.3 Relevant Controls 1.4 The Subject Buildings 1.5 Scope of the Assessment 1.6 The Project Team

2.0 Key Issues for Consideration 18 2.1 Key Issues for BCA Compliance 2.2 Key Issues for Housing Code Compliance 2.3 Key Issues for Essential Conservation Works

3.0 Compliance Summary of Each Building Type 24

4.0 Physical Intervention for Each Building Type 26 4.1 Option 1 Essential Conservation and Compliance Works 4.2 Option 2 Upgrade towards Contemporary Standards 4.3 Option 3 Residential Accommodation Augmentation

5.0 Internal Unit Area Outcomes 32

6.0 Cost Analysis for Each Option 34

7.0 Comparative Market Values of the Precinct 35

8.0 Assessment of Heritage Impact 37 8.1 Heritage Significance of Northbourne Housing Precinct 8.2 Effects on Architectural Integrity (Option One) 8.3 Effects on Architectural Integrity (Option Two) 8.4 Effects on Architectural Integrity (Option Three) 8.5 Assessment of Physical Impacts (Options One and Two) 8.6 Impact on Significance (Options One and Two) 8.7 Impact on Significance (Option Three)

9.0 Conclusions and Recommendations 45 9.1 Background 9.2 Interventions and Impacts 9.3 Heritage Impact Assessment 9.4 “Feasible and Prudent” Alternative 9.5 Relationship with the Griffin Plan

10.0 Attachments 50



Executive Summary

Background This Summary Report has been prepared at the request of ACT Land Development Agency (LDA) in the context of an application (DA 291425880) for demolition of three buildings, known as the Dickson Bedsitter Flats, on Block 40-41 Section 6 Dickson. The site of the Dickson Bedsitter Flats is within the Northbourne Housing Precinct. When the demolition application was lodged in mid 2014, the Northbourne Housing Precinct as a whole had been nominated for provisional registration to the ACT Heritage Register. On 18 September 2014, ACT Heritage Council Provisionally Registered the Northbourne Housing Precinct on the ACT Heritage Register. On 29 July 2014, ACT Heritage Unit advised LDA that they required more information as to “Feasible and Prudent” Alternatives to the proposed demolition of the Dickson Bedsitter Flats. This Summary Report and its attachments provide that information. The current demolition application for the Dickson Bedsitter Flats is likely to be the forerunner of larger scale development across the whole Precinct as set out in the 2014 Master Plan. Accordingly, the assessment of “Feasible and Prudent” Alternatives summarised in this Report has been undertaken across all five building types that comprised the completed 1962 Northbourne Housing Precinct. The overall Northbourne Housing Precinct comprises three parcels of land and five different building types:

• Block 40 and 41, Section 6, Dickson, comprising three Dickson Bedsitter Flats buildings

• Block 8, Section 51, Lyneham, comprising the single Lyneham Bedsitter Flats

building, the De Burgh Paired Houses and the Owen Flats buildings

• Block 1, Section 12 and Block 4, Section 1, Dickson, comprising the Karuah Maisonettes buildings and the Karuah Garden Flats buildings

Heritage Related Alternative Options In heritage terms, any detailed consideration of “Feasible and Prudent Alternatives” must start with an examination of the capacity of the existing buildings to undergo essential fabric conservation and be upgraded but only to the extent of reasonable compliance with the Building Code of Australia (BCA) and the ACT Multi-Unit Housing Code. It is an important for the buildings to be capable of certification for compliance with relevant standards and codes. This will enable future finance and insurance arrangements to be made by private dwelling owners. The solution developed as a basis for the basic level of assessment is identified as Option One, which examines the extent of conservation and compliance work to bring the Precinct to BCA and ACT Multi-Unit Housing Code compliance, but without any additional refurbishment of kitchens, bathrooms, communications etc. Above the basic model, Option Two assumed that, in accordance with a typical approach to historic house renovation, kitchens and bathrooms would be upgraded and that some internal demolition would be undertaken to open up the relatively small internal spaces. Both Option One and Option Two were based on the retention and conservation of the original external building envelopes, adding only larger balconies to the Owen Flats and new balconies to the upper level Bedsitter Flats.



Option Three, the augmentation of accommodation for the various dwelling types generated a large increase in cost and a degree of change that was considered to be beyond what would constitute a “Prudent” alternative in heritage terms. Accordingly, the assessment of Option Three did not continue to an examination of the issue of “Feasibility” in terms of the market valuation.

Feasible and Prudent Alternatives The examination of “Feasible and Prudent” Alternatives for the Northbourne Housing Precinct rests on potentially competing outcomes. Essential conservation and compliance upgrade works can be undertaken on the Northbourne Housing Precinct in a manner that conserves the overall Heritage Significance and all of the features intrinsic to the heritage significance of the place, identified in the Provisional Heritage Registration. Minor impacts on the architectural integrity and clarity of the original urban planning will be generated by alterations to the Owen Flats balconies and new balconies to the Bedsitter Flats, and the introduction of a new pattern of private courtyard walls. There will also be a small reduction in the number of dwelling units due to amalgamations within the Dickson and Lyneham Bedsitter Flats buildings to meet minimum dwelling area standards. In heritage terms, the conservation and upgrade option and can be regarded as a “Prudent” Alternative to the extensive demolition contained within the 2014 Master Plan. In economic terms, the difference between the two outcomes is considerable. The conservation alternative (Option One) generates some 157 dwellings and a market valuation of approximately $15 million compared with approximately 1099 dwellings and $70 million for the 2014 Master Plan. The broader economic impacts between the two alternatives are however significant. There is a considerable quantum differential between the two alternatives in terms of both return to Government and stimulus to the ACT economy. In economic terms, the conservation and upgrade option is difficult to justify as a “Feasible” Alternative to the 2014 Master Plan.



1.0 Introduction and Background

1.1 Introduction This Summary Report has been prepared at the request of ACT Land Development Agency (LDA). It has been prepared in the context of an application (DA 291425880) for demolition of three buildings, known as the Dickson Bedsitter Flats, on Block 40-41 Section 8 Dickson, submitted in June 2014 on behalf of the LDA. The site of the Dickson Bedsitter Flats is within what is known as the Northbourne Housing Precinct. When the demolition application was lodged, neither the subject buildings nor the Northbourne Housing Precinct as a whole were formally listed on the ACT Heritage Register, although the entire Precinct had been nominated for provisional registration to the ACT Heritage Register. In accordance with Part 10 of the Heritage Act 2004 the Demolition Application for the Dickson Bedsitter Flats buildings was referred to the ACT Heritage Council for advice. Subsequent to the referral, ACT Heritage Unit advised LDA in a letter dated 29 July 2914, that being mindful of ss3(3) of the Act, they required more information as to “Feasible and Prudent” Alternatives to the proposed demolition of the Dickson Bedsitter Flats. In addition, information should be provided that confirms all measures to reasonably minimise adverse impacts have been taken. (Attachments 1 and 1a). The term “Feasible and Prudent” is not defined in the Dictionary within the Act. Additional information was requested about potential impacts on the planning values of the Precinct related to the Griffin’s planning legacy (Attachment 11). This Summary Report and its attachments provide that information. The current demolition application for the Dickson Bedsitter Flats is likely to be the forerunner of larger scale development across the whole Precinct as set out in the 2014 Master Plan. In their letter to LDA dated 3 July 2014, with respect to a presentation of the 2014 Master Plan to the Development Application Taskforce, the ACT Heritage Council also requested information on “Feasible and Prudent” Alternatives to the Master Plan. Accordingly, the assessment of “Feasible and Prudent” Alternatives summarised in this Report has been undertaken across all five building types that comprised the completed 1962 Northbourne Housing Precinct. The overall Northbourne Housing Precinct comprises three parcels of land:

• Block 40 and 41, Section 6, Dickson, comprising three Dickson Bedsitter Flats buildings

• Block 8, Section 51, Lyneham, comprising the single Lyneham Bedsitter Flats building, the De Burgh Paired Houses and the Owen Flats buildings

• Block 1, Section 12 and Block 4, Section 1, Dickson, comprising the Karuah Maisonettes buildings and the Karuah Garden Flats buildings

On 18 September 2014, ACT Heritage Council provisionally registered the Northbourne Housing Precinct on the ACT Heritage Register. The current assessment of “Feasible and Prudent” Alternatives has concentrated on the scope of works necessary to achieve a baseline option (Option One) of essential conservation works plus BCA and Housing Code compliance. Beyond that a second option (Option Two), which includes internal modernisation of living areas, bathrooms and kitchens, was examined. Both these options generally confined the works to the existing building envelopes. Both can be regarded as acceptable in terms of best practice heritage conservation. Certification will enable future finance and insurance arrangements to be made by private dwelling owners.



A third alternative, Option Three explored the augmentation of accommodation for the various dwelling types, but generated a large increase in cost and a degree of change that was considered to be beyond what would constitute a “Prudent” alternative. Accordingly, the assessment of Option Three did not continue to an examination of the issue of “Feasibility” in terms of the market valuation. This Report summarises a broad range of investigations across the entire Northbourne Housing Precinct, including essential conservation works, upgrading required for BCA and ACT Multi-Unit Housing Code Compliance, likely costs and market valuation comparisons between conservation (Options One and Two) and redevelopment (the 2014 Master Plan)

ACT Heritage Policy Background As the Precinct has only formally reached the Provisional Registration stage, no formal Heritage Guidelines have yet been prepared. However, ACT Heritage General Conservation Policy 5 - Demolition in Heritage Places provides a Conservation Objective and Policy Elements for partial or total demolition of heritage places in the ACT. Although this policy is not mandatory, it represents the best practice for heritage conservation, endorsed by the ACT Heritage Council, and it will be used by the Council when providing advice on proposed changes. Conservation Objective To preserve the historical integrity of heritage places. Policy Elements The specific impacts of demolition should be considered in the light of the following policies for Heritage Places:

1. Total demolition of heritage places … should not be permitted except in exceptional circumstances, including:

• The building is structurally unsound as to be beyond economic repair.

• The existing condition poses a significant health or safety risk that is beyond economic repair.

The proposal contained in the 2014 Master Plan for Northbourne Housing Precinct retains some of the De Burgh Paired Houses for commercial use but demolishes all other buildings. The decision by the ACT Government to prepare the Master Plan was made in the wider policy context of generating funds for the provision of contemporary social housing, increasing the densification of urban development along major public transport corridors such as Northbourne Ave and generation of funding for infrastructure within the ACT. The extent of proposed demolition in the 2014 Master Plan was not predicated on the structural soundness or general condition of the subject buildings. Accordingly, this report has responded to the following statement within the ACT Heritage guidance document Development at Heritage Sites: Proposed changes which negatively impact on heritage significance will only be permitted where it is proven that there is no feasible and prudent alternative.

Public Housing Policy Background The ACT has the oldest public housing portfolio in Australia with an average age of properties being 29 years. Many of the dwellings no longer meet the requirements of public housing tenants. These properties have poor amenity and energy efficiency which impacts on the cost of living expenses for tenants. Maintenance and repair costs on the ageing portfolio are also increasing as the buildings age.



Multi unit properties are not the most appropriate allocations for clients with high and complex needs. Both the Commonwealth and other jurisdictions have been committed to reducing “concentrations of disadvantage”. Redevelopment of public housing sites provides an opportunity to create attractive and environmentally sustainable redevelopment of ageing public housing stock. The relocation of tenants from the Northbourne Housing Precinct will assist with breaking down the concentrations of disadvantaged in this site, in accordance with the ACT commitments under the National Affordable Housing Agreement and the National Affordable Housing Agreement and the National Partnership Agreement on Homelessness. The ACT Government is committed to the delivery of more socially sustainable mix of dwellings. The ACT Government is also committed to applying all the funds generated by any redevelopment of multi unit properties back into public housing. The Government has committed to a “roof-for-roof” replacement policy. The benefits of this policy will be that public housing tenants are provided with modern, well designed and efficient housing, that is better suited to their needs and that will enable them to age in place. It is intended that tenants will be relocated into smaller developments throughout Canberra.

Urban Development and Public Transport Objectives Greater yields generated by increasing residential density on existing, relatively low scale multi-unit public housing sites are required, if the proposed redevelopment and replacement of public housing is to be financially viable. Redeveloping and increasing density will not only contribute to the replacement on a “roof-for-roof” basis aged public housing stock, it will assist by providing seed funding for the Capital Metro Project. Wider demographic and economic benefits to the ACT will also be delivered through increasing residential density for sites on the major public transportation corridors, especially those relatively close to the city and major suburban centres.

Budgetary Context An examination of “Feasible and Prudent” Alternatives to the selection of the Northbourne Housing Precinct as one of the initial sites for sale and development should also be framed in the context of the public dialogue concerning the ACT Budget. The ACT Territory faces a big economic challenge because of the Commonwealth's budget cuts. These cuts will impact upon the economy and the ACT budget. The ACT Government is focused upon delivering the services and infrastructure needed to support the city through this challenging period. It is also focused on encouraging growth in the future. This will help the ACT community, particularly the most vulnerable, businesses and households. It will also create and protect jobs. The ACT Government has chosen to invest in Canberra and support the community. Growing the economy is a priority. Over the next four years, $2.5 billion has been allocated for infrastructure projects. This will boost job growth across the city and support new projects such as a new University of Canberra Public Hospital, the new Coombs school, a new CIT Campus in Tuggeranong, new road and light rail infrastructure, new cycling and walking paths, renewal of the Woden Town Centre, new public buildings like the Court Facilities project and Australia Forum Convention Centre, and the City to the Lake Project. Of particular importance to this consideration is the desire by the ACT Government to fund and build the proposed Capital Metro project, which will see a new light rail service introduced along Northbourne Avenue. Assets, including the Callum Offices at Woden, Macarthur House on Northbourne Avenue, and aging public housing in the inner north (including the Northbourne Housing Precinct), have been earmarked for potential sale and redevelopment – in part to finance infrastructure projects. It is anticipated that this policy initiative will help maintain growth in the ACT economy and support jobs, provide vital services and facilities, and deliver the transformative infrastructure needed for the long term.



The ACT Planning Strategy (2012) promotes development within urban areas and particularly consolidation within Town Centres. The realization of development along the Northbourne Housing Precinct will assist in progressing delivery of this Government program, as well as contribute to achieving the target of 50% of new housing within the existing urban area, within 5 years. This project is also consistent with the ACT Planning Strategy 2012 and the liveable cities project ‘Realizing the Capital in the City’ which amongst other things promotes the redevelopment of public housing immediately to the east and north of the city.

Heritage Related “Feasible and Prudent” Alternative Options In heritage terms, any detailed consideration of “Feasible and Prudent Alternatives” must start with an examination of the capacity of the existing buildings to undergo essential fabric conservation and be upgraded but only to the extent of reasonable compliance with the Building Code of Australia (BCA) and the ACT Multi-Unit Housing Code. It is an important for the buildings to be capable of certification for compliance with relevant standards and codes. This will enable future finance and insurance arrangements to be made by private dwelling owners. The solution developed as a basis for the basic level of assessment is identified as Option One, which examines the extent of conservation and compliance work to bring the Precinct to BCA and ACT Multi-Unit Housing Code compliance, but without any additional refurbishment of kitchens, bathrooms, communications etc. Above the basic model, Option Two assumed that, in accordance with a typical approach to historic house renovation, kitchens and bathrooms would be upgraded and that some internal demolition would be undertaken to open up the relatively small internal spaces. Both Option One and Option Two were based on the retention and conservation of the original external building envelopes, adding only larger balconies to the Owen Flats and new balconies to the upper level Bedsitter Flats. As noted above, Option Three, the augmentation of accommodation for the various dwelling types generated a large increase in cost and a degree of change that was considered to be beyond what would constitute a “Prudent” alternative in heritage terms. Accordingly, the assessment of Option Three did not continue to an examination of the issue of “Feasibility” in terms of the market valuation.

Feasible and Economic Assessment Finally to test the “Feasibility” of the conservation and compliance upgrades the scope of work for all options was itemised and cost estimates for were sourced from a Quantity Surveyor. Comparative Market Value information was also sourced for conservation/upgrading (Option One) and comprehensive redevelopment of the Precinct (2014 Master Plan). This information was then considered from a broad feasible and economic perspective as well as the strategic whole of government requirement to upgrade public housing and utilise public property assets to the best advantage.

The Realities of Conservation Within the assessment of the three conservation options for the Northbourne Housing Precinct a number of reality checks were identified. The final Assessment of Heritage Impact for the three Options will take these realities into consideration when determining if they can be described as “Feasible and Prudent”.

• The architectural and urban planning clarity of the original Precinct, as illustrated in photos by Max Dupain, has been overlaid by factors such as age, use, amenity screening to Northbourne Avenue, private courtyards, minor alterations and upgrading over time and a mature if poorly managed landscape. If modern Code compliance must be achieved it is highly unlikely that the 1960s clarity can be realistically and reasonably recaptured.



• Housing Code compliance requires a new series of external private courtyards for some of the building types. It is assumed that the design of new courtyards will be integrated with the reconstruction of the original pattern of pergolas that were a distinctive linking feature between buildings across the Precinct. Nevertheless, it will be practically impossible to totally recapture the pattern of generous open, shared landscape spaces between buildings that was a fundamental characteristic of the Post War International Modernism adopted by Sydney Ancher and NCDC for the original Precinct.

• While the basic building construction techniques and materials of the original Precinct

were “mainstream” for the time, the building fabric has endured a long service life and periods of deferred maintenance. Much of the original external fabric, in particular roofs, roof drainage, timber window and door joinery will need to be replaced if it cannot be repaired or cannot meet current BCA and Code compliance requirements.

• The fire resistance rating requirements for the Owen and Dickson Flats buildings in

particular, is reliant to a large extent on the degree of concrete cover over the reinforcing steel in the floor slabs between dwelling units. Core sample testing has indicated that the slabs are close to adequacy, however for compliance they will rely on the introduction of internal sprinkler systems. Sprinklers will also assist in achieving other alternative BCA compliance solutions.

• The existing mature landscape across the entire Precinct needs to be modified by

removing subsequently planted or self-seeded material and trees that have reached the end of their anticipated life. New planting will be introduced within the Precinct to balance and complement retained trees.

While this Report does not discuss potential disposal and future ownership directions, it does assume that the conservation and upgrading of the approximately 169 dwellings would be undertaken in a comprehensive and unified manner. The Precinct was developed as a single entity by NCDC in the early 1960s. The highly distinctive and important unity of expression and presentation in architectural and civic design, urban planning and landscaping terms was only achieved by the strong overall project coordination and implementation imposed by NCDC. Accordingly, this report assumes that a similar level of conservation and repair standards and coordinated project implementation requirements would be imposed for an upgrading programme as was developed for the 2014 Master Plan for comprehensive redevelopment.



The potential conservation and upgrading of the Northbourne Housing Precinct can largely recapture the architectural character, but never realistically achieve the purity of the urban

composition illustrated in Max Dupain’s original photographic record



1.2 The Three Conservation and Upgrading Options

Option 1 Essential Conservation and Compliance In accordance with the recognition given to the Northbourne Housing precinct by its Provisional Registration to the ACT Heritage Register, the essential scope of conservation and compliance upgrading works required for the Essential Conservation and Compliance Option comprises:

• An in-depth assessment of the architectural character and construction of the original buildings, based on the 1960s drawings and some site analysis.

• Conserve and recapture, as much as reasonably possible, the clarity of the original

1960s architectural character and planning layouts. This will include removing subsequent additions and site works, removal of hazardous material such as bonded asbestos, conservation and where necessary replacement of the external fabric, retention where possible of internal room layouts, kitchen and bathroom fittings, reconstruction of the original pergola layout that linked many of the buildings together, and careful removal of secondary landscaping, while retaining major trees that are still in good condition.

• Upgrade individual building types to meet current BCA compliance requirements,

including the installation of sprinklers in the Owen and Bedsitter Flats buildings, to achieve alternative compliance and avoid otherwise major physical interventions.

• Upgrade individual building types to meet the relevant applicable requirements of the

ACT Multi-Unit Housing Code, including conversion of some units for easy access, reclassification or joining together of some units to ensure compliance with minimum unit area standards, provision of required minimum size external balconies to upper level flats and private open space at ground level, minimum parking numbers etc.

• Upgrade existing Precinct-wide services infrastructure, pathways and driveways,

including new garden walls for private open landscaped space and landscaping. The extent of the Option One conservation and compliance works, establishes a baseline outcome for the existing buildings, and Precinct as a whole. They will be conserved and upgraded to be capable of current code certification and presentation to the market for residential sales. The major negative external architectural impacts are confined to the Owen Flats and the Bedsitter Flats Buildings which will require alteration to or addition of the upper level balconies. To a lesser degree the Karuah Flats and Paired Houses will also be impacted externally by the upgrading of the balcony balustrades. The clarity and purity of the original network of the shared open space between the Paired Houses will not be recaptured. In heritage terms, this Option creates the potential for a positive heritage outcome in relation to the features that are intrinsic to the heritage significance of the Northbourne Housing Precinct. However, the internal combining of the Bedsitter Flats does generate a small reduction in the total number of dwelling units within the Precinct.



Option 2 Upgrade towards Contemporary Residential Standards In addition to the baseline case in Option One, a number of additional works packages were identified to provide the buildings with facilities and standards that may make them more attractive in the contemporary residential marketplace. Such upgrades can be regarded as relatively standard approaches when historic residential properties are being renovated to contemporary standards, albeit while still being confined within the volume of the existing external walls and roof. These include:

• Selective internal demolition and open up of relatively small internal room layouts by combining service and/or kitchen/dining/living rooms into more generous spaces.

• Replacement of Kitchen and Bathroom fittings, storage and equipment to

contemporary standards, within the restrictions provided by individual dwelling units.

• Installation of modern cable based communication systems to all dwellings. In heritage terms, this Option creates the potential for a positive heritage outcome in relation to the features that are intrinsic to the heritage significance of the Northbourne Housing Precinct. However, the internal combining of the Bedsitter Flats does generate a small reduction in the total number of dwelling units within the Precinct. However the cost of conservation and compliance works are greater than Option One. The same negative impacts, as described above in Option One, apply to this Option.

Option 3 Residential Accommodation Augmentation In addition to the above Options, a third Option was developed by the architects to test and demonstrate the extent of works, and therefore the likely heritage impacts, of providing larger dwelling unit areas within the various building types. While this Option provides expanded dwelling sizes, there is a considerable impact on the internal fabric and external architectural integrity of the original buildings. The extent of works assessed included:

• Almost total internal demolition across all building types to facilitate rearrangement of room layouts, new private stair access etc.

• New rear additions on Owen Flats and Karuah Maisonettes

• New side additions to Garden Flats

• Infill of shared courtyard and deck spaces for Paired Houses

• The combination of units on each floor of the Bedsitter Flats buildings, previously

considered as part of this option has been moved to Option 1 in order to meet minimum area requirements.

Extensive augmentation of the existing buildings generated a large increase in cost and a degree of internal and external change to the historic buildings that was considered to be beyond what would constitute a “Prudent” alternative. Accordingly, the assessment of Option Three did not continue to an examination of the issue of “Feasibility” in terms of the market valuation.



1.3 Relevant Controls Each “Feasible and Prudent” conservation and upgrading option for the buildings must respond to the relevant requirements of the following: Provisionally Registered Place under ACT Heritage Act As from 18 September 2014, the Northbourne Housing Precinct been provisionally Registered to the ACT Heritage Register. The conservation and upgrading of the buildings, and the Precinct, needs to protect and seek to enhance the established Heritage Significance of the Precinct. A separate Statement of Significance was developed by Graham Brooks and Associates during the formulation of the 2013 Conservation Management Plan and Statement of Heritage Effects for the 2014 Northbourne Master Plan. However, this assessment of “Feasible and Prudent Alternatives” has been prepared to assist ACT Heritage review those alternatives. Accordingly, the formal Statement of Heritage Significance, contained in the Provisional Registration, and the associated Features Intrinsic to the Heritage Significance of the Place will be used as the basis for the Assessment of Heritage Impact. Building Code of Australia Any conservation and upgrading of the buildings must ensure that the completed outcome comply the requirements of the Building Code of Australia. Where strict compliance with the BCA is likely to generate unacceptable intervention into historic building fabric, spaces or architectural character, alternative compliance provisions can be explored and implemented, subject to the formulation of fire engineered solutions, particularly in relation to the installation of sprinklers in the Owen and Bedsitter Flats buildings. ACT Multi-Unit Housing Code The subject Precinct is located within the area covered by the Northbourne Ave Precinct Code. This requires that all of the conservation and upgrading of buildings within the Northbourne Housing Precinct are controlled by the provisions of the ACT Multi-Unit Housing Code.



1.4 The Subject Buildings The analysis of “Feasible and Prudent Alternatives” was undertaken for all five of the building types within the Northbourne Housing Precinct. These are:

• Karuah Garden Flats (single storey) • Karuah Maisonettes(three storeys) • De Burgh Paired Houses (two storeys) • Owen Flats (three storeys) • Dickson and Lyneham Bed Sitter Flats (four storeys)

The site plan below (CGR/AMW) provides the key to the location of the various buildings within the overall Northbourne Housing Precinct.

Site Plan and Building Identification

1.5 Scope of the Assessment

Scope of Assessment The scope of the heritage related “Feasible and Prudent Alternatives” analysis summarised in this document and supported by the various Appendices, included:

• Building Code of Australia Compliance, including Acoustic Performance • Sprinkler installation in Owen and Bedsitter Flats for alternative BCA compliance • Non-invasive structural slab construction in Bedsitter Flats to ascertain fire rating • General structural condition • ACT Multi-Unit Housing Code Compliance • Identification of three options and preparation of architectural sketches • QS Estimates of Cost for the three Options • Heritage Impact Assessment of the three Options to text their “Prudent” outcomes in

relation to the heritage significance of the Precinct • Market valuations of Option One for conservation and compliance compared with the

development yields generated by the 2014 Master Plan.



Assessment Methodology The following interactive steps were taken by the consultant team as part of the analysis. Note that due to a desire to avoid tenancy disruption within the short analysis timeframe and with information gathered on previous site visits, it was decided that the analysis would be done using only documentary evidence. No specific site inspections were considered necessary for this report, as the consultant team is familiar with the precinct, having visited the precinct on numerous occasions in the past. The methodology adopted by the consultant team included:

• Undertake detailed review of the original architectural drawings to confirm the nature of the construction (essentially mainstream load bearing brickwork with some steel columns within the dwelling and concrete upper floor slabs) and the relevant dimensions to inform the BCA and Code assessment

• Undertake detailed BCA revue of the different housing types to determine areas of

non-compliance and identify actions that could be taken to achieve compliance (Attachment 2 with supplementary acoustic reports and sprinkle design layouts)

• Undertake detailed analysis of the building types in relation to Housing Code

compliance requirements (Attachment 3)

• Prepare architectural drawings illustrating the degree of intervention and refurbishment for Option One Upgrade (Attachment 4)

• Undertake visual inspection of the buildings to ascertain general structural

performance after a decades-long working life (Attachment 5)

• Undertake core sampling of the perimeter beam at First Floor level and non-invasive investigation of upper floor concrete slabs to ascertain depth of concrete cover over the reinforcing steel to predict fire resistance of existing floor slabs (Attachment 6)

• Prepare architectural drawings illustrating the degree of intervention and

refurbishment for Option Two Upgrade (Attachment 7)

• Prepare architectural drawings illustrating the degree of intervention and new works for the Option Three upgrade (Attachment 8)

• Review of the general condition and integrity of the buildings and their settings within

the Northbourne Housing Precinct, given their age, progressive alterations over time and extent of deferred maintenance in recent years

• Summarise the essential compliance works required for both the BCA and the ACT

Multi Unit Housing Code for each building type.

• Summarise the physical interventions for each building type, taking into account the various specialist analyses and the need for general refurbishment of the building fabric and site elements. The likely effects on the original integrity of the individual building types arising from the identified interventions are then summarised.

• Prepare Cost Summaries and Cost Breakdowns for all three Options based on

identified scope of works (Attachments 9a to 9f)

• Undertake Market Valuations of Option One/Two for conservation and compliance compared with the development yields generated by the 2014 Master Plan. (Attachment 10) Option Three was not taken forward into Market Valuation stage.

• Review the 1960s Northbourne Housing Precinct development in terms of whether it

met some of the ideals or objectives of the early Griffin Plan. (Attachment 11)



1.6 Project Team The analyses were undertaken by the following firms:

• Conrad Gargett Riddel / Ancher Mortlock Woolley, (CGR/AMW) Architects • Blackett Maquire + Goldsmith, BCA Consultants • Wilkinson Murray Acoustic Consultants (for specific BCA compliance issues) • Coutts Cost Consulting, Quantity Surveyors • Michael Frost and Associates, Hydraulic Engineers (for sprinkler design) • AECOM, Structural Engineers, (for assessment of structural condition of the Dickson

Bedsitter buildings and fire resistance ratings of the concrete floor slabs) • Colliers International (for market valuations)

The project was coordinated by Graham Brooks, Director, Graham Brooks and Associates, Heritage Consultants. Graham had been the author of the detailed Statements of Heritage Impact for the Dickson Bedsitter flats demolition DA and the overall Northbourne Housing Precinct Master Plan.



2.0 Key Issues for Consideration

2.1 Key Issues BCA Compliance

Building Types, Number of Storeys and Construction Classification The number of rise in storeys and use of a building establishes the basic parameters for an examination of BCA compliance issues. The subject buildings are all residential, single attached dwellings and apartment dwellings, with the following rise in storeys:

• Karuah Garden Flats (single storey) • Karuah Maisonettes(three storeys) • De Burgh Paired Houses (two storeys) • Owen Flats (three storeys) • Dickson Bed Sitter Flats (four storeys)

Structural Adequacy The structural adequacy of a building is essentially related to the methods of construction and the materials used. The various building types in the Northbourne Housing Precinct were all erected with load bearing brick walls and concrete floors, using a well established building construction methodology for the period. The main conclusions of the AECOM Inspection Report (pp10) are as follows:

• A visual inspection of the structural condition of one of the Dickson Bedsitter buildings indicates that there is little evidence of cracking or significant settlement. The overall structural condition of the buildings is generally good for their age (50+ years), with only cosmetic defects in the main structural elements. Secondary structures including the carport and rear screens have more significant structural defects that will require maintenance in the short to medium term.

• The buildings were completed in 1962, which makes them over 50 years of age. The current version of AS3600 – Concrete Structures Code limits its application with respect to durability to structures with a design life of 40 to 60 years. While these buildings would have been designed to an older version of this code, the reinforced concrete elements should be considered near the end of their nominal design life as far as durability is concerned.

Core samples of representative upper floor slabs, the First Floor perimeter beam and columns revealed the following:

• Thickness of suspended slabs ranges from 180-200mm. They suspect that the design depth may have been 7 inches (180mm)

• Concrete cover to the slab soffit is in excess of 30mm (typically 35-45mm as

measured in several locations)

• The current concrete code requires a minimum slab thickness for this type of building of 200mm, which means the slab is slightly too thin to meet the Deemed to Satisfy provisions of the current BCA. However, the non-conformance is so minor that I would not pursue it and it could easily be overcome during a building refurbishment.



In relation to this finding, the BCA Consultant responded: For the purpose of this exercise an opinion on the required fire resistance level of the floor slab is the primary focus, i.e. an FRL of 90/90/90 is required for a class 2 building of Type A Construction. In the case of an opinion that the existing structure does not fully meet these requirements (as implied in the AECOM review), then we believe the introduction of an automatic fire sprinkler system to the building can be utilised to enable a fire safety engineer to formulate an alternative solution, such as a sprinkler installation, that justifies that fire resistance has been provided to the degree necessary. In summary, we are of the view that the existing floor slab could remain in place subject to a fire engineered alternative solution. AECOM also reported the core samples revealed that the depth of carbonation of the main beam at First Floor Level supporting the upper walls of the Bedsitter Buildings appears to have reached to the same depth as the reinforcing steel. There is some rusting and spalling of concrete associated with rusting reinforcing steel in one small area of the beam. They suggest that this is evidence that the concrete structure has reached or is approaching the end of its design life. While AECOM suggest that remediation of spalling concrete and rusting reinforcing steel require long, expensive and repetitive cyclical repair, such concrete conservation such repair techniques are now relatively mainstream and can be factored into any conservation and long term maintenance programmes. No specific testing was undertaken for the upper floor slabs in the Owen Flats. However, given the consistency of the original construction methods across the Precinct, it can be reasonably be assumed that the proposed sprinkler system will satisfy the required compliance standards for a fire engineers solution

Fire Resistance Separation The nature of the construction of the various buildings is that walls between adjoining units are regarded as providing the required fire resistance rating. In some areas the floor slabs are supported by unprotected steel pipe columns. Without the installation of sprinkler systems, these columns would need protection.

Ceiling Heights The typical clear ceiling height in the main living areas of the Northbourne dwellings is a little in excess of 2400mm. While this ceiling height may be regarded as low by contemporary multi-unit housing standards, it is sufficient to comply with BCA requirements, especially as the dwelling units have relatively small floor areas.

Emergency Exits Common stairs in the multi-dwelling buildings, in this case the Bedsitter Flats and Owen Flats, must have a minimum clear part of travel and be fitted with handrails on both sides. Site measurements of the common stairs in the Bedsitter Flats and Owen Flats revealed the following:

• Dickson Bedsitter Flats currently have 1070mm clear between the wall and the existing handrail. The half landings are typically 2260 long but only 980 wide.

• The Owen Flats have 1040mm clear between the wall and the existing handrail.



On the basis that the installation of a second handrail to the common stairs may reduce the width of the path of travel to below 1 metre, advice was sought from the BCA Consultant. A 1m unobstructed width for a path of travel to an exit is the minimum prescribed by the deemed-to-satisfy provisions of the BCA. Essentially, 1m width can cater for up to 100 occupants of a building. There is a low population at each storey of the Bedsitters apartments and the Owen Flats, significantly less than 100 persons per floor. Generally, it is considered that evacuation will occur in a single file arrangement. In this instance, should additional handrails within the development result in the unobstructed width being less than 1m (evidently by up to say 50mm at stairs and less than 1m at landings), it could readily be argued from a Fire Engineering perspective that there is adequate room within the stair to allow safe egress from the building in an emergency. This will take into account the likelihood of occupants exiting in single file and also the ergonomics of the human movement and what is considered sufficient area. Therefore, we do not consider that significant intervention into the fabric is required to justify that egress can comply with the Performance Requirements of the BCA as a result of the additional handrail. Ground floor exit doors must open outwards. Non complying doors will need to be re-hung. The Bedsitter Flats building, with a total of four storeys, require that the main access stair be located in a fire rated shaft, meaning that doors to sole occupancy units cannot open directly into the stair, as is the current case, unless the dwelling occupies the whole of the floor level. Compliance with the Housing Code has generated a proposal to combine the two flats on each upper floor to achieve minimum space standards. This solution resolves the BCA issue.

Balustrade and Stair Handrails Balustrades to private balconies, internal and common access stairs to all buildings with the exception of the Garden Flats, must be upgraded to meet minimum height and clear spacing criteria. Allowance has been made to replace or upgrade all balcony and stair handrails.

Alternative Solutions (Sprinklers) A number of construction, fire resistance and escape stair issues regarding BCA compliance can be overcome by the installation of sprinklers into the Owen Flats and Bedsitter Flats buildings. As this solution provided the most cost effective and least intrusive outcome, the assessment has been prepared on the assumption that sprinklers would be installed. Due to the complying but minimal clear ceiling heights, the sprinkler pipes would be run at cornice level within the individual units and side throw sprinkler heads would be installed.

Access In BCA terms, the primary requirement is that disabled access is provided to the entry door of ground floor units. This applies primarily to the Owen Flats and the Bedsitter Flats. In addition, all dwellings must now have internal bathroom doors re-swung to open outwards in order to achieve sufficient clearance for emergency access.

Services Upgrade In general all of the internal services, heating, hot water, communications, lighting, electrical and emergency lighting within all dwellings will require upgrading.



Acoustic Performance between dwellings In general, the construction of walls separating dwellings in the flats buildings and attached houses comply with the required acoustic performance for airborne and impact transmissions. The floors between separate dwellings in the Owen and Bedsitter Flats buildings are generally considered to be satisfactory, provided carpets are laid in living areas and some additional insulation is added where bathrooms and kitchens are located above each other.

Environmental Performance All external glazing must conform to AS 2047. This will require the replacement of all external glazing on all buildings. It is highly likely that the timber windows and glazed walls will require extensive repair or replacement, partly to ensure that they can adequately support the new glazing and meet sealing criteria.

2.2 Key Issues Housing Code Compliance

Minimum Dwelling Floor Area and Reclassification In many cases the original Northbourne Housing dwelling units are now below the minimum space standards set by the Code. The dwellings were designed to suit public housing standards current in the late 1950s and strict compliance with size was a major form of project cost control exercised by the NCDC. Minimum areas are currently 40 m² for studios, 50m² for one bed units, 70m² for two bedroom units and 95m² for three bed units. As a result of the current Codes, many of the units within the Precinct must be reclassified downwards, reducing the overall unit type yield, but not the unit number yield. In the case of the Bedsitter Flats, the current small size of each unit resulted in the decision to combine the two dwellings on each floor to create a complying dwelling. The numerical yield was thus reduced from seven units per building to four.

Private Open Space at Ground Level The mid 1970s saw construction of a series of face brick courtyard walls, especially facing Northbourne Avenue, to create private open space for the Paired Houses and Karuah Maisonette buildings. This resulted in a significant impact on the important network of common open spaces between buildings that was a fundamental characteristic of the Post War International Urban Design of the Northbourne Precinct. Carefully integrated privacy walls had been an original feature of the Paired Houses and to some extent of the Karuah Maisonettes and a major feature of the Garden Flats. The 1970s additions obscured this clarity and saw the demolition of some of the original Paired Houses privacy walls. For all ground floor dwellings, the Code requires 24m² of private open space, with a minimum dimension of 4m, opening directly from the day time living area. This will generate the need for a network of courtyard walls to the Owen Flats and Bedsitter Flats buildings that were never part of the original or evolved Precinct. It will also require a new network of courtyard walls to the Paired Houses and Karuah Maisonettes buildings. The Garden Flats have the required open space as an integral component of their original design.

Minimum Dimensions for Balconies The Code also requires each upper level unit to the fitted with a balcony of at least 8m², with a minimum dimension of 1.8m. This means that all balconies to the upper level units in the Owen Flats must be expanded. All upper level units in the Bedsitter Flats must be fitted with new external balconies. Furthermore transparent balustrades must not be fitted to balconies on the lowest four storeys.



Accessible Dwellings The Code requires that 10% of the dwellings of any multi-unit housing must meet the Australian Standard and Access & Mobility General Code. This resulted in one of the existing Ground Floor units in each Owen Flats building being altered internally to meet this requirement. In addition, the existing Ground Floor unit in the Bedsitter Flats buildings was converted to meet access requirements as well as expanded to meet the minimum space standards.

Sun Shading and Weather Protection The Code requires that windows located on west facing facades should be fitted with external sunshades which are integrated into the building design. The required sun shading is to be in addition to any high performance glazing.

Parking Provision On the assumption that Visitor Parking is generally catered for in surrounding streets, the biggest impact of Code compliance with regard to parking is the additional 12 spaces to be provided for the Owen Flats.

Site Infrastructure It has been assumed for cost estimation purposes that the majority of existing site infrastructure services will need to be upgraded. As the number of dwellings in Options One and Two is not increasing, there has been no allowance for major augmentation of site infrastructure.

2.3 Key Issues Essential Conservation Works

Conserve the External Building Envelope The original external envelopes of the various buildings on the Northbourne Housing Precinct utilised a very limited palette of materials to achieve time and construction cost advantages. External walls were generally finished with a pre-coloured “Tyrolean” render, roofs were profiled metal sheeting, often over a concrete roof slab and all external glazing was fitted in timber relatively standardised painted timber framing. All of the buildings are now over 60 years old and have endured a long service life as publicly supported housing, minor alterations by tenants, previous upgrades such as the provision of external courtyards to provide private open space, and deferred maintenance in recent years.. Conservation of buildings of this age, in conjunction with the various BCA and Code compliance upgrades, has led to a number of assumptions for this aspect of the works. These include replace all metal roofs, gutters and downpipes to original profiles or a reasonable close match, repair or replace all timber external door and window glazing in accordance with its condition and required upgrade, undertake concrete repairs as necessary to prevent continuing spalling, and repair the existing pre-coloured render as far as possible, or replace to closely match existing finishes.

Conservation of Interiors It is highly likely that many of the fittings, finishes and/or fittings in kitchens and bathrooms have been progressively altered over the years, or have deteriorated from a long service life. Option One assumes that the existing kitchen and bathrooms can be renovated to retain and repair existing fittings etc. Option Two assumes that kitchens and bathrooms can be upgraded to contemporary design and market standards, generally within the existing spaces, or after minor opening up of the original internal spaces.



Asbestos Removal It is highly likely that the existing buildings will contain some form of bonded asbestos, most likely in wet areas, as backing to non-ceramic floor and wall tiles, and possibly used as insulation for pipework. While bonded asbestos is not generally recognised as a heath hazard for occupants, any renovation project needs to include removal of all asbestos products in the building. A full hazardous materials inspection of the buildings will be required and material either removed or safely encapsulated, subject to expert advice. The cost estimates include for asbestos removal.

Remove Later Accretions Over the years various tenants in a number of the buildings and dwellings have added a variety of blinds and screens, enclosures, pergolas, obscure glazing, storage structures and other appurtenances. All of these will be removed. It is assumed that all dwellings will be transferred into to a conservation project as vacant possession.

Recapture early Design and Planning Imagery The biggest alterations to the early design and planning imagery were the removal of the pergola network and the introduction courtyard walls and privacy screens to Northbourne Avenue. Alterations have also been made to the free standing garages and carports associated with the Owen and Bedsitter Flats. All later screens and courtyard walls will be removed. Subject to careful design, new courtyard walls will be introduced as requited for Housing Code compliance and integrated with a reconstruction of the original pergola and screen layouts

Landscape Conservation Mature early trees that remain in good condition and retain a reasonable life expectancy, will be retained within the Precinct. Registered trees will also be retained. A new landscape scheme that responds to the early planting schemes will be prepared and implemented.



3.0 Compliance Summary of Each Building Type The compliance assessment of each building type against BCA and Multi-Unit-Housing Code has been summarised below. Refer to Attachments 2 and 3 for full assessment. Single Storey Dwellings: BCA and Housing Code Applies to Karuah Garden Flats Compliance Issue

Required Action

Fire resistance of external walls Complies External glazing to AS 2047 Allow for reglazing all external glass Access to bathrooms within dwellings Rehang bathroom doors Natural lighting and ventilation Complies Smoke alarms Install smoke alarms Energy Efficiency Upgrade window seals and equipment Hot Water supply Upgrade HW supply system Insulation to HW, heating and cooling supply Upgrade pipe and ductwork Lighting Upgrade lighting 10% of dwellings to meet access and mobility code

Internal alterations for accessible bathroom

Minimum horizontal dimension between primary and secondary windows

Alterations to internal courtyard windows

External sun screening devices to west Complies if screens added Private open space at ground level Complies within courtyards External clothes drying facilities Complies if courtyards amended Parking 12 Additional Spaces required on site and 4

visitor spaces on street Two and Three Storey Dwellings: BCA and Housing Code Applies to De Burgh Paired Houses and Karuah Maisonettes Compliance Issue

Required Action

All Matters raised for Single Storey Dwellings Upgrade in a similar manner Walls separating Class 1 dwellings Complies Verandah Balustrades Allow for replacement with complying Internal Stair balustrades Allow for replacement with complying Limit opening of windows above ground floor Install required window furniture Waterproofing of external balconies Install waterproofing Fire separation between Paired Dwellings Construct ground floor wall to separate the

shared courtyards/parking spaces 10% of dwellings to meet access and mobility N/A Minimum horizontal dimension between primary and secondary windows

Complies

External sun screening devices to west Complies if screens are added Private open space at ground level Complies if courtyard walls are reworked External clothes drying facilities Complies if courtyard walls are reworked Parking Paired Houses require 12 visitor spaces on

street Karuah Maisonettes comply

Non transparent balcony balustrades facing Northbourne Ave

Complies if balustrades are altered



Three and Four Storey Apartment Buildings: BCA and Housing Code Applies to Owen Flats and Dickson and Lyneham Bedsitter Flats Compliance Issue

Required Action

All Matters raised for all Dwellings as above Upgrade in a similar manner Fire rating of load bearing walls and floors Complies as sprinkler system is proposed Fire rating of internal steel columns Complies as sprinkler system is proposed Multiple unit entry doors cannot open into a single common fire stair

Complies as sprinkler system is proposed

Fire stopping at underside of roof Allow to fire stop connections between roof and walls surrounding individual units

Entry doors to individual units Replace with complying fire doors & frames Combustible external timber wall panelling Replace with non-combustible material Service Risers Upgrade fire seals Common stair exit doors Adjust to open outwards Common area electrical distribution boards Protect doors with smoke separation Access to ground floor common areas Upgrade access to common laundries Fire Hydrants Provide new or upgrade existing Fire extinguishers Provide in common stair at each floor level Emergency Lighting and signage Upgrade as necessary Maintenance work sanitary facility Provide in each Owen Flats building Acoustic separation between dwelling units for hard floor finishes (except bathrooms)

Complies if floor finish is carpet Insulation to be installed in cavity walls between units in Owen Flats

Section J upgrade Upgrade as required 10% of dwellings to meet access and mobility One Ground Floor unit in each building to be

altered and fitted out as accessible Minimum horizontal dimension between primary and secondary windows

Complies

External sun screening devices to west Complies if screens are added Private open space at ground level New courtyard walls required External clothes drying facilities New courtyard walls required for Bedsitter

Flats Parking Owen flats comply but need 12 Visitor spaces

on the rear street or within the site Bedsitter Flats comply as reduced unit numbers due to amalgamation to meet minimum unit size in Code

Non transparent balcony balustrades facing Northbourne Ave

Complies if balustrades are altered, especially on Bedsitter Flats

Provision of external balconies to upper units Bedsitter Flats need to be fitted with new external balconies to achieve compliance and Living Room glazing altered to include balcony door

Minimum area and width of balconies Upper level balconies to Owen Flats need to be widened to achieve compliance



4.0 Physical Intervention for Each Building Type

4.1 Option One - Essential Conservation and Compliance The following physical interventions will be required for the essential conservation and compliance upgrade of each building type. Refer to Attachment 4

Karuah Garden Flats BCA Compliance Works

• Replace all glazing panels to meet AS 2047 • Re-swing internal bathroom doors and fit with removable door hinges • New Smoke Alarms in accordance with AS 2047 • Window and door seals in accordance with AS 2047 • Exhaust fans fitted with sealing device • Seal of skirtings, architraves, cornices and light fittings • New hot water systems and insulated pipe work to AS/NZS 3500.4 • New lighting and electrical wiring and meters • New internal heating • Repair or renew domestic gas installation

Housing Code Compliance Works

• N/A for the Garden Flats Essential Conservation Works

• Repair external pre-coloured render, including to courtyard walls • Repair or upgrade roof, gutters, downpipes and stormwater drainage • Repair or replace external timber joinery, windows, doors, fascias and pergolas • External and internal painting • New internal floor coverings and ceilings to service areas • Replace Carport doors • Replace or repair driveway and carport paving • Replace or repair private and common area pergolas and fences • New courtyard and common area paving and landscaping

Karuah Maisonettes BCA Compliance Works

• Replace all glazing panels to meet AS 2047 • Re-swing internal bathroom doors and fit with removable door hinges • New Smoke Alarms in accordance with AS 3786 • Window and door seals in accordance with AS 2047 • Install window opening limiting devices to upper levels • Exhaust fans fitted with sealing device • Seal of skirtings, architraves, cornices and light fittings • New hot water systems and insulated pipe work to AS/NZS 3500.4 • New lighting and electrical wiring and meters • New internal heating • Repair or renew domestic gas installation • Replace balustrades to external balconies to meet BCA Clause 3.9.2.2 and structural

adequacy AS/NZS 1170.1 and waterproof balconies. • Replace balustrades to internal stairs to meet BCA Clause 3.9.2.3 and structural

adequacy AS/NZS 1170.1



Housing Code Compliance Works • Balcony balustrades facing Northbourne Ave to be non transparent • Remove external courtyard walls installed in the 1970s • Install a series of new private courtyard walls • Fit external sunscreens to west facing windows

Essential Conservation Works

• Repair external pre-coloured render, including to courtyard walls • Repair or upgrade roof, gutters, downpipes and stormwater drainage • Repair or replace external timber joinery, windows, doors, fascias and pergolas • External and internal painting • New internal floor coverings and ceilings to service areas • Replace Carport doors • Replace or repair driveway and carport paving • Replace or repair private and common area pergolas and fences • New courtyard and common area paving and landscaping

De Burgh Paired Houses BCA Compliance Works

• Ground floor doors to common stairwells to open outwards • Rebuild ground floor walls between adjoining car spaces • New non-combustible screen at First Floor to separate upper, shared terrace • Replace all glazing panels to meet AS 2047 • Re-swing internal bathroom doors and fit with removable door hinges • New Smoke Alarms in accordance with AS 3786 • Window and door seals in accordance with AS 2047 • Install window opening limiting devices to upper levels • Exhaust fans fitted with sealing device • Seal of skirtings, architraves, cornices and light fittings • New hot water systems and insulated pipe work to AS/NZS 3500.4 • New lighting throughout • New Electrical wiring and meters • New internal heating • Repair or renew domestic gas installation • Replace balustrades to external balconies to meet BCA Clause 3.9.2.2 and structural

adequacy AS/NZS 1170.1 and waterproof balconies. Balcony balustrades facing Northbourne Ave to be non transparent

• Replace balustrades to internal stairs to meet BCA Clause 3.9.2.3 and structural adequacy AS/NZS 1170.1


• Balcony balustrades facing Northbourne Ave to be non transparent • Remove external courtyard walls installed in the 1970s • Install a series of new private courtyard walls integrated with the reconstructed

pergola layout • Fit external sunscreens to west facing windows


• Repair external pre-coloured render, including to courtyard walls • Repair or upgrade roof, gutters, downpipes and stormwater drainage • Repair or replace external timber joinery, windows, doors, fascias and pergolas • External and internal painting • New internal floor coverings and ceilings to service areas • Replace or repair driveway paving • Replace or repair common area pergolas and fences



Owen Flats BCA Compliance Works

• Install fire rated doors to all unit entries • Install fire hydrant and fire extinguishers to each level in common stairs • Install automatic fire sprinkler system throughout the building • Rebuild upper level balconies to all units to minimum Code dimensions • Ground floor doors to common stairwells to open outwards • Install maintenance staff WC on ground floor • Rebuild all free standing garages to improve common area open space • Replace external timber panelling with non-combustible panelling • Replace all glazing panels to meet AS 2047 • Re-swing internal bathroom doors and fit with removable door hinges • New Smoke Alarms in accordance with AS 3786 • Window and door seals in accordance with AS 2047 • Install window opening limiting devices to upper levels • Exhaust fans fitted with sealing device • Seal of skirtings, architraves, cornices and light fittings • Seal all duct and riser penetrations through floors and common walls • Acoustic upgrade to floors and ceilings as required • New hot water systems and insulated pipe work to AS/NZS 3500.4 • New lighting throughout and emergency lighting in common stairwells • New Electrical wiring and meters • New internal heating • Repair or renew domestic gas installation • Replace balustrades to external balconies to meet BCA Clause 3.9.2.2 and structural

adequacy AS/NZS 1170.1 and waterproof balconies. Balcony balustrades facing Northbourne Ave to be non transparent

• Replace balustrades to internal stairs to meet BCA Clause 3.9.2.3 and structural adequacy AS/NZS 1170.1


• Convert one ground floor unit in each building for accessibility • New private courtyards to ground floor units • Alter upper level balconies to suit the minimum area and width dimensions • Fit external sunscreens to west facing windows


• Balcony balustrades facing Northbourne Ave to be non transparent • Repair external pre-coloured render, including to courtyard walls • Repair or upgrade roof, gutters, downpipes and stormwater drainage • Repair or replace external timber joinery, windows, doors, fascias and pergolas • External and internal painting • New internal floor coverings and ceilings to service areas • Replace or repair driveway paving • Replace or repair common area pergolas and fences • New landscaping to common areas



Bed Sitter Flats BCA Compliance Works

• Install fire rated doors to all unit entries • Install fire hydrant and fire extinguishers to each level in common stairs • Install automatic fire sprinkler system throughout the building • Install new upper level balconies to all units to minimum Code dimensions • Ground floor doors to common stairwells to open outwards • Rebuild all free standing garages to improve common area open space • Replace all glazing panels to meet AS 2047 • Re-swing internal bathroom doors and fit with removable door hinges • New Smoke Alarms in accordance with AS 3786 • Window and door seals in accordance with AS 2047 • Install window opening limiting devices to upper levels • Exhaust fans fitted with sealing device • Seal of skirtings, architraves, cornices and light fittings • Seal all duct and riser penetrations through floors and common walls • Acoustic upgrade to floors and ceilings as required • New hot water systems and insulated pipe work to AS/NZS 3500.4 • New lighting throughout and emergency lighting in common stairwells • New Electrical wiring and meters • New internal heating • Repair or renew domestic gas installation • Replace balustrades to external balconies to meet BCA Clause 3.9.2.2 and structural

adequacy AS/NZS 1170.1 and waterproof balconies • Replace balustrades to internal stairs to meet BCA Clause 3.9.2.3 and structural

adequacy AS/NZS 1170.1 Housing Code Compliance Works

• Convert ground floor unit in each building as an accessible unit • Convert remnant part of ground floor space for private storage • Completely demolish the internal walls while retaining the original stairways • New private courtyards to ground floor units • Convert the two existing units on each upper floor into a single dwelling to achieve

minimum required dwelling flor area • Install external balconies outside the Living Room windows of upper level units and

convert window unit to door unit • Fit external sunscreens to west facing windows


• Repair external pre-coloured render, including to courtyard walls • Repair or upgrade roof, gutters, downpipes and stormwater drainage • Repair or replace external timber joinery, windows, doors, fascias and pergolas • External and internal painting • New internal floor coverings and ceilings to service areas • Replace or repair driveway paving • Replace or repair common area pergolas and fences • New landscaping to common areas

Common Areas

• Upgrade Fire Hydrant infrastructure • Upgrade site services power, water, sewer, stormwater, gas • Upgrade common Parking, Driveways and Internal Roads • Conserve major cultural plantings and Registered Trees • Upgrade landscaping to all common areas



4.2 Option Two - Upgrade towards Contemporary Residential Standards

The following physical interventions will be required for the essential conservation and compliance upgrade of each building type. Refer to Attachment 7 In addition to the works outlined for Option One, Option Two included the following;:

Karuah Garden Flats

• Selective internal demolition and alterations to increase the efficiency of internal planning and spatial allocation for Living Room

• New internal storage • Upgrade Kitchen, Bathrooms and Laundry fit-out

Karuah Maisonettes

• Selective internal demolition and alterations on Ground Floor to increase the efficiency of internal planning and spatial allocation for Laundry and WC.

• Selective internal demolition and alterations on First Floor to increase the efficiency of internal planning and spatial allocation for Living/Dining/Kitchen

• Selective internal demolition and alterations on Second Floor to increase the efficiency of internal planning and spatial allocation for additional bathroom and storage to Bedroom 1

• Upgrade Kitchen, Bathrooms and Laundry fit-out

De Burgh Paired Houses

• Selective internal demolition and alterations on Ground Floor to increase the efficiency of internal planning and spatial allocation for Laundry and Kitchen.

• Selective internal demolition and alterations on First Floor to increase the efficiency of internal planning and spatial allocation for Bedrooms and Bathrooms

• Upgrade Kitchen, Bathrooms and Laundry fit-out

Owen Flats

• Selective internal demolition and alterations within all units, with the exception of the alterations already described to create the accessible unit, to increase the efficiency of internal planning and spatial allocation for Living/Dining/Kitchen

• New private storage cupboards in common stairwells • Upgrade Kitchen, Bathrooms and Laundry fit-out

Bedsitter Units No additional physical intervention over and above Option One



4.3 Option Three - Residential Accommodation Augmentation The following physical interventions will be required for the essential conservation and compliance upgrade of each building type. Refer to Attachment 8 In addition to the works outlined for Options One and Two, the Augmentation Option included the following:

Karuah Garden Flats Two versions were prepared, one for each of the original Garden Flats typology

• Demolish all internal walls • Completely reorganise the internal accommodation within the original building volume • Provide a single storey addition to the rear of the building that increases the original

footprint by about 60% for new Kitchen and Living Room. The new extension would be fitted with a higher roof to provide high level glazing for more light and internal special volume

Karuah Maisonettes Two versions were prepared

• Demolish all internal walls and staircases at all levels • Completely reorganise the internal accommodation within the original building volume • Build an elevated two or three storey rear addition with shared staircases for the inner

four units and new internal staircases for the outer two units in each block • Install sprinkler system to enable BCA alternative compliance approach

De Burgh Paired Houses

• Demolish all internal walls and staircases at all levels • Completely reorganise the internal accommodation • Build new two storey infill for new private stairs and additional bathrooms, replacing

the paired open courtyards between the dwellings • Completely reorganise the internal accommodation within the original building volume

Owen Flats

• Demolish all internal walls and staircases at all levels • Completely reorganise the internal accommodation within the original building

volume. The original unit floor area will be largely devoted to larger Living, Dining and Kitchens

• Build an elevated three storey rear addition to provide one or two bedrooms for each original dwelling unit

• Install sprinkler system to enable BCA alternative compliance approach

Bed Sitter Flats

• No additional physical intervention over and above Option One



5.0

Internal Unit Area Outcomes

5.1 Existing Accommodation Item Lyneham &

Dickson bedsits Deburgh PH

Owen Flats

Karuah Maisonettes

Karuah Garden Flats

Site Area 5,675m2 20,800m

2 5,250m

2 5,400m

2 7,525m

2 approx

Dwellings -

• Bedsitter (XXm

2 per

dwelling)

28dw(7x4) 37.5m

2

N/A N/A N/A N/A

• One Bedroom (XXm

2 per

dwelling)

N/A N/A 24 dw (6x4) 42.5m

2

N/A 4 dw 65.65m

2

• Two Bedroom (XXm

2 per

dwelling)

N/A N/A 24 dw (6x4) 56.5m

2

N/A 12 77m

2

• Three Bedroom (XXm

2 per

dwelling)

N/A 47dw 98m2

N/A 30 dw(6x5) 100m2

N/A

GFA m2

• Residential 1,360m2 4,606m2 306m2 3,000m2 1,187m2 (approx. area)

5.2 Options One and Two Compliance Item Lyneham &


Owen Flats

Karuah Maisonettes

Karuah Garden Flats


2 5,250m

2 5,400m

2 7,525m

2

Dwellings -

• Bedsitter (XXm

2 per

dwelling)

N/A N/A 24dw (6x4) 42.5m

2

N/A N/A

• One Bedroom (XXm

2 per

dwelling)

4 dw (1x4) 52.5m

2

N/A 24 dw (6x4) 56.5m

2

N/A 4 dw 65.65m

2

• Two Bedroom (XXm

2 per

dwelling)

12 dw (3x4) 75m2

N/A N/A 12dw 77m2

• Three Bedroom (XXm2 per

dwelling)

N/A 47dw 2 bed +study/3 bed) 98m

2

N/A 30dw (6x5) 100m2

N/A

GFA m2

• Residential 1,360m2 4,606m2 3,060m

2 3,000m

2 1,187m

2

(approx area)



5.3 Option Three Residential Augmentation Item Lyneham &


Owen Flats

Karuah Maisonettes

Karuah Garden Flats


2 5,250m

2 5,400m

2 + 7,525 m2 + (1,550m

2

when road reserve included)

Dwellings -

• Bedsitter (XXm2 per

dwelling)

N/A N/A N/A N/A N/A

• One Bedroom (XXm2 per

dwelling)

4 dw(1x4) 52.5m

2

N/A 24 dw (6x4) 75m

2 (1

bed & Study)

40 dw (8x5) 58.5m

2

N/A

• Two Bedroom

• (XXm2 per

dwelling)

12 dw (3x4) 75m

2

N/A 24dw (6x4) 75m

2 -

12dw + 94 m2 – 12 dw (2 bed + study)

10 dw (2x5) 87m

2

4 90m

2

• Three Bedroom (XXm

2 per

dwelling)

N/A 47dw 122.75m

2

N/A N/A 12dw 135m

2

GFA m2

• Residential 1,360m2 5,769m

2 4,628 m

2 4,200m

2 1,980m

2

(approx area)



6.0 Cost Analysis for Each Option Detailed cost analysis has been undertaken by Coutts Consulting, Quantity Surveyors (Attachment 9). In summary the total anticipated construction costs, including 15% contingency and 15% site management fees, for the various Options are as follows:

Option One Building or Works Package Projected Cost De Burgh Paired Houses $5,252,250 Owen Flats $6,063, 200 Karuah Maisonettes $3,081,000 Karuah Garden Flats (1 Bedroom) $324,000 Karuah Garden Flats (2 Bedroom) $1,238,400 Dickson Bedsitter Flats $2,645,600 Lyneham bedsitter Flats $881,870 External Works $1,305,250 Additional Parking $120,000 Site Services and Infrastructure $853.400 Total Estimate for Option One $21,720,300

Option Two Building or Works Package Projected Cost De Burgh Paired Houses $8,777,000 Owen Flats $6,063,200 Karuah Maisonettes $5,790,500 Karuah Garden Flats (1 Bedroom) $519,000 Karuah Garden Flats (2 Bedroom) $1,858,800 Dickson Bedsitter Flats $2,645,600 Lyneham bedsitter Flats $881,870 External Works $1,305,250 Additional Parking $120,000 Site Services and Infrastructure $853.400 Total Estimate for Option One $28,773,150

Option Three Building or Works Package Projected Cost De Burgh Paired Houses $12,029,050 Owen Flats $20,815,050 Karuah Maisonettes $10,329,000 Karuah Garden Flats (1 Bedroom) $1,226,800 Karuah Garden Flats (2 Bedroom) $4,125,600 Dickson Bedsitter Flats $2,612,100 Lyneham bedsitter Flats $870,700 External Works $1,305,250 Additional Parking $120,000 Site Services and Infrastructure $853.400 Total Estimate for Option One $41,526,300



7.0 Comparative Market Values of the Precinct Comparative Market valuation (Attachment 10) of the properties has been provided on two scenarios:

• Conservation Options One and Two – the Precinct listed on the ACT Heritage Register, with conservation and compliance works completed, and a slightly reduced dwelling yield.

• 2014 Master Plan - highest and best use for the Northbourne Housing Precinct, with

approvals in place, for retention and re-use of some of the Paired Houses plus higher density residential development. Note that the existing Blocks 40 and 41 containing the Dickson Bedsitter Flats will be renamed Block 44 after the proposed amalgamation within the Master Plan.

The existing Northbourne Housing Precinct contains a total of 169 dwellings. With a reduction in the number of dwellings in the Dickson and Lyneham Bedsitter Flats buildings by combining two flats into one on each floor to achieve minimum dwelling size, the final unit mix in the conservation scenario is 157, comprising: Block 44, Section 6, Dickson Dickson Bedsitter Flats buildings 3 x 1 Bedroom 9 x 2 Bedrooms Block 8, Section 51, Lyneham Lyneham Bedsitter Flats building 1 x 1 Bedroom 3 x 2 Bedrooms De Burgh Paired Houses 47 x 3 Bedrooms Owen Flats buildings 24 x 1 Bedroom 24 x 2 Bedrooms Block 1, Section 12 and Block 4, Section 1, Dickson Karuah Maisonettes buildings 30 x 3 Bedrooms Karuah Garden Flats buildings 4 x 1 Bedroom 12 x 2 Bedrooms Total 157 Dwellings By contrast, the 2014 Master Plan generated some 1099 dwellings plus commercial space in the retained and upgraded De Burgh Paired Houses. The valuations have been prepared in accordance with the Australian Property Institute (API) and the Property Institute of New Zealand (PINZ) and New Zealand Valuation and Property Standards. Colliers International provided these assessments. Conservation Options One and Two Valuation Block 44, Section 6, Dickson $500,000 Block 8, Section 51, Lyneham $9,000.000 Block 1, Section 12 and Block 4, Section 1, Dickson $5,600.000 Total Current Valuation $15,100,000 2014 Master Plan Valuation Block 44, Section 6, Dickson $10,140,000 Block 8, Section 51, Lyneham $34,360.000 Block 1, Section 12 and Block 4, Section 1, Dickson $25,870.000 Total Current Valuation (before demolition) $70,370,000



In addition to the comparative market valuation of the two scenarios, Colliers International have advised of the wider economic benefits to the ACT Government from the implementation of each of the alternative options. The wider economic benefits, in terms of taxes and construction generated by development from each option are detailed below: Revenue Source

Conservation Option 2014 Master Plan

Transaction revenue, comprising: Stamp duty on sale of sites within the overall Precinct

$750,000 $3,500,000

Stamp duty on sale of individual dwellings

$2,100,000 $20,000,000

GST payable under margin scheme

$3,000,000 $30,000,000

On-going general rates and taxes (per annum)

$275,000 $1,650,000

Construction work for the economy

$25,000,000 $325,000,000

Based upon the Colliers advice, it may be concluded that there is a significant economic benefit from the implementation of the 2014 Master Plan.



8.0 Assessment of Heritage Impact

8.1 Heritage Significance of Northbourne Housing Precinct A separate Statement of Significance was developed by Graham Brooks and Associates during the formulation of the 2013 Conservation Management Plan and Statement of Heritage Effects for the 2014 Northbourne Master Plan. However, this assessment of “Feasible and Prudent Alternatives” has been prepared to assist ACT Heritage review those alternatives. Accordingly, the formal Statement of Heritage Significance, contained in the Provisional Registration, and the associated Features Intrinsic to the Heritage Significance of the Place will be used as the basis for this Assessment of Heritage Impact.

STATEMENT OF HERITAGE SIGNIFICANCE The Northbourne Housing Precinct (the Precinct), designed and constructed between 1959 and 1962, is of considerable significance for its creative achievement including its architectural style, as a distinctive design of exceptional interest, as a rare and notable example of types of public housing, and for strong associations with important figures, the NCDC, and the post-war period in Canberra. The Precinct is significant as an exemplar example of Post War International (1940-1960) architecture demonstrating key attributes of the style including cubiform overall shape, expression of structural frames and large sheets of glass. (criteria (a), (c) and (g)). The Precinct is important as evidence of a distinctive post war government policy for the provision of subsidised housing in Canberra and makes an important contribution to the understanding of this development phase through its distinctive and innovative planning layout, design and siting (criteria (c), (g) and (h)). The Precinct is rare in the public housing flat development projects in post-war Canberra for its highly resolved and consistent application of Post-War International Modernism in its site planning and architectural resolution. The project was the only project of the era to utilise a combination of five building and accommodation types, ranging from single storey garden flats, two storey paired houses, three storey Maisonettes, three storey blocks of flats to four storey bachelor flats. (criterion (f)) The innovative planning layout and design demonstrates a significant shift in the approach to providing public housing for the influx of public servants to the capital. The National Capital Development Commission (NCDC) recognised a need to provide a range of accommodation types to meet a range of lifestyles and accommodation needs, as compared with what had previously been provided in the blocks of flats of the early 1950s. The Precinct created an innovative and strongly rectilinear composition of five distinctively different building types and siting arrangements, “internal” service roads, networks of pergolas and pathways and the resultant variety of common open spaces, the majority of which directly addressed Northbourne Avenue, represents an innovative step forward for medium density public housing in the ACT. (criterion (a)) The NCDC acknowledged the significance of the Precinct’s location on a main approach route into the capital and therefore designed the Precinct to present as a “gateway” into the capital as evidenced by the placement of the four storey bachelor flats or “Point Blocks” at the northern end of the Precinct, and in the Precinct’s distinctive Post-War International style of architecture. (criterion (a)) The Precinct has strong associations with Sydney Ancher (architect) and Sir John Overall (client), both of whom through their respective organisations, created a major public project that played a significant part in the development of Canberra in the early 1960s. The combination of Sydney Ancher (Senior partner in Ancher Mortlock & Murray), a leading



exponent of the Post-War International Modernist style in his domestic architecture since 1945, and John Overall, commissioner of the newly created National Capital Development Commission (NCDC) and other senior staff, achieved a project with a high level of civic design and architectural expression (criteria (a) and (h)).

FEATURES INTRINSIC TO THE HERITAGE SIGNIFICANCE OF THE PLACE

The attributes listed below are assessed as features intrinsic to the heritage significance of the place and warrant conservation:

• All buildings comprising the existing combination of five building types known as:

1. The Bachelor (Bedsitter) Flats (four storeys) 2. The Pair Houses (two storeys) 3. The Maisonettes (three storeys) 4. The garden Flats (Courtyard Houses) (single storey) and 5. The Three Storey Flats (Owen Flats) (three storeys)

• And their arrangements in groups and inter-relationships within sub-precincts

• The application of Post-War International style architecture across the five building

types

• The existing rectilinear planning layout and building siting arrangements including “internal” service roads, networks of pathways and a variety of common open spaces addressing Northbourne Avenue

• The separation of vehicle and pedestrian movement and the restriction of vehicle

access to secondary roads

• The early pattern of mature landscaping along Northbourne Avenue frontages and in the common courtyards , rear streets and cul-de-sacs.



8.2 Effects on Architectural Integrity (Option One) The works identified for Option One will have the following effects on the fundamental feature that is intrinsic to the heritage significance of the Northbourne Housing Precinct – the architectural integrity of the of the individual and groups of five different building types.

Karuah Garden Flats

• Some minor internal replanning • General upgrading of building services • New internal colour schemes and floor coverings

De Burgh Paired Houses • Some minor internal replanning • General upgrading of building services • New internal colour schemes and floor coverings • Replace external balcony balustrades • Replace internal stair balustrades • Reorganised private courtyard walls • Balcony balustrades facing Northbourne Ave to be non transparent

Karuah Maisonettes • Some minor internal replanning • General upgrading of building services • New internal colour schemes and floor coverings • Replace external balcony and internal stair balustrades • Reorganised private courtyards • Balcony balustrades facing Northbourne Ave to be non transparent • Some minor internal replanning • General upgrading of building services • New internal colour schemes and floor coverings • Expanded external balcony and internal stair balustrades • Enlarged external balconies to the upper floors • Conversion of one Ground Floor unit to accessible configuration • Creation of Ground Floor maintenance staff WC • Balcony balustrades near Northbourne Ave to be non transparent

Bedsitter Flats • Major internal replanning • General upgrading of building services • New internal colour schemes and floor coverings • Replace internal stair balustrades • New external balconies to the upper floors • Conversion of Ground Floor unit to accessible configuration

Overall Precinct • Reconstructed private and common area pergolas and fences



8.3 Effects on Architectural Integrity (Option Two) In addition to the effects generated by Option One, the additional works associated with Option Two will have the following effects.

All Buildings • Selective internal demolition and alterations within all units, with the

exception of the alterations already described to create the accessible unit, to increase the efficiency of internal planning and spatial allocation for Living/Dining/Kitchen

• New private storage cupboards in common stairwells • Upgraded Kitchen, Bathrooms and Laundry fit-out

8.4 Effects on Architectural Integrity (Option Three) The augmentation of the various buildings in Option Three will result in:

Garden Flats • Expansion of the original building envelope • Distortion of original architectural scale and character • Complete loss of original internal planning layout including stairs

De Burgh Paired Houses • Expansion of the original building envelope • Distortion of original architectural scale and character • Complete loss of original internal planning layout including stairs

Karuah Maisonettes • Expansion of the original building envelope • Distortion of original architectural scale and character • Complete loss of original internal planning layout including stairs

Owen Flats • Expansion of the original building envelope • Distortion of original architectural scale and character • Complete loss of original internal planning layout including stairs

Bedsitter Flats • Complete loss of original internal planning layout



8.5 Assessment of Physical Impacts (Options One and Two) Garden Flats Positive Heritage Impacts

Negative Heritage Impacts

• Conservation of deteriorated external materials, finishes and detailing

• Internal upgrade to contemporary BCA requirements

• New Kitchen and Bathroom fittings and fixtures

• General upgrading of building services • New internal colour schemes and floor

coverings • Reconstruction of original pergola and

fence layouts to central courtyards • Upgraded landscaping to common area

• No negative impacts

De Burgh Paired Houses Positive Heritage Impacts







fence layouts to central courtyards • Upgraded landscaping to common areas

• Replacement of upper level balcony balustrades

• Replacement of internal stair balustrades • Non transparent balcony balustrades

facing Northbourne Avenue • New private courtyards

Karuah Maisonettes Positive Impacts

Negative Impacts








• Replacement of internal stair balustrades • Non-transparent balcony balustrades

facing Northbourne Avenue • New Private courtyards



Owen Flats Positive Heritage Impacts










near Northbourne Avenue • Reorganisation of the Ground Floor unit

as an accessible occupancy • New private courtyards to Ground Floor

units

Bedsitter Flats Positive Impacts

Negative Impacts







• Complete reorganisation of internal planning and space utilisation on the upper floors

• Complete reorganisation of the Ground Floor unit as an accessible occupancy

• Installation of new external balconies and conversion of window unit to balcony door access will distort architectural integrity


facing Northbourne Avenue • New private courtyards to Ground Floor

unit



8.6 Impact on Significance (Options One and Two) The impact on the provisionally registered overall Heritage Significance of Northbourne Avenue Housing Precinct arising from the proposed Essential Conservation Options (One and Two) will generally be positive in heritage terms. Both adopt mainstream approaches to the conservation and upgrading of historic houses. In terms of an assessment, for Options One and Two, of the impact on the Features Intrinsic to Heritage Significance of the Place:

• All of the buildings comprising the existing combination of five building types will be retained, conserved and upgraded to BCA and Housing Code compliance within their existing building volumes and essential architectural imagery.

• The original arrangements in groups and the inter-relationships within sub-precincts

will be recaptured and largely retained.

• The distinctive and important Post War International style of architecture used across the five building groups, including the monochromatic rendered cubiform volumes, consistent application of architectural details and floor to ceiling window units is retained.

• The existing rectilinear planning layout and building siting arrangements including

“internal” service roads, networks of pathways, pergolas and a variety of common open spaces addressing Northbourne Avenue, will be retained.

• The separation of vehicle and pedestrian movement and the restriction of vehicle

acess to secondary roads, will be retained.

• The early pattern of mature landscaping along Northbourne Avenue frontages and in the common courtyards, rear streets and cul-de-sacs, will be retained or recaptured.

As discussed in Section 1.0, a number of contemporary issues impose upon the comprehensive recapture of the original 1960s project.

• The architectural and urban planning clarity of the original Precinct, as illustrated in photos by Max Dupain, has been overlaid by factors such as age, use, amenity screening to Northbourne Avenue, private courtyards, minor alterations and upgrading over time and a mature if poorly managed landscape. Modern Code compliance will limit to some extent the potential to recapture the 1960s clarity.

• Housing Code compliance requires a new series of external private courtyards for

some of the building types. It is assumed that the design of new courtyards will be integrated with the reconstruction of the original pattern of pergolas that were a distinctive linking feature between buildings across the Precinct. Nevertheless, it will be practically impossible to totally recapture the pattern of generous open, shared landscape spaces between buildings that was a fundamental characteristic of the Post War International Modernism adopted by Sydney Ancher and NCDC for the original Precinct.

• While the basic building construction techniques and materials of the original Precinct

were “mainstream” for the time, the building fabric has endured a long service life and periods of deferred maintenance. Much of the original external fabric, in particular roofs, roof drainage, timber window and door joinery will need to be replaced if it cannot be repaired or cannot meet current BCA and Code compliance requirements.

• The fire resistance rating requirements for the Owen and Dickson Flats buildings in

particular, is reliant to a large extent on the degree of concrete cover over the reinforcing steel in the floor slabs between dwelling units. Core sample testing has



indicated that the slabs are close to adequacy, however for compliance they will rely on the introduction of internal sprinkler systems. Sprinklers will also assist in achieving other alternative BCA compliance solutions.

• The existing mature landscape across the entire Precinct needs to be modified by


The major negative external architectural impacts are confined to the Owen Flats and the Bedsitter Flats Buildings from the alteration to or addition of upper level balconies. To a lesser degree the Karuah Flats and Paired Houses will also be impacted externally by the upgrading of the balcony balustrades.

Assessment of “Feasible and Prudent” Outcome In heritage terms, conserving and upgrading to BCA and Housing Code compliance, as captured in Options One and Two, can be regarded as “Prudent” Alternative to the extent of demolition generated by the 2014 Master Plan. In economic term, the conservation and upgrade option is not a “Feasible” Alternative to the 2014 Master Plan. The cost to undertake the required conservation and upgrade works is significant when compared to residual market value. In addition, the economic benefits generated by the 2014 Master Plan are considerable compared to the conservation and upgrade option..

8.7 Impact on Significance (Option Three) Extensive augmentation of the existing buildings is not considered to have a satisfactory outcome in heritage terms, given the widespread intervention internally and the extent of the external alterations and additions. There will be extensive impacts on the external and internal architectural integrity of virtually every building in the Precinct. This option was examined as part of the 2010 Master Plan, at which time it was combined with a major residential redevelopment of the overall Precinct. However, as a stand alone project, the resultant overall yield of total dwellings is not significantly larger than the existing. This makes it hard to justify the additional work and the loss of architectural and urban planning integrity in heritage terms. In heritage terms, residential accommodation augmentation is not regarded as a “Prudent or Feasible Alternative”.



9.0

Conclusions

9.1 Background

1. This detailed analyses of heritage related “Feasible and Prudent Alternatives” in relation to the proposed demolition of the three Dickson Bedsitter Flats buildings in the Northbourne Housing Precinct has focussed on the extent of essential physical intervention required to meet compliance and conservation objectives and assessed the likely impact on the heritage significance of the Precinct, and the Dickson Bachelor Flats in particular.

2. A fundamental aspect of the overall Northbourne Ave Precinct project is that the

property has been identified by the ACT Government for sale to fund other infrastructure development.

3. The examination of “Feasible and Prudent Alternatives” in heritage terms has been

undertaken on the basis that the completed buildings can be certified as complying with relevant standards and codes. This will enable future finance and insurance arrangements to be made by potential private dwelling owners.

9.2 Interventions and Impacts

1. In general all of the buildings will require extensive external conservation, including removal of later accretions, repair of pre-coloured render, repair and possibly replacement of external timber joinery and complete replacement of roofing and rainwater disposal goods.

2. In general all buildings can reasonably reach BCA compliance, although extensive

physical interventions will be required. The primary impacts being replacement of stair and balcony balustrades and the installation of sprinklers in the Owen Flats and Bedsitter Flats buildings to enable alternative compliance to be achieved.

3. The greatest unknown factor with BCA compliance is the existing fire resistance

capacity of the concrete floor slabs in the Owen Flats and Bedsitter Flats. Non-destructive testing has revealed but not confirmed that there appears to be sufficient concrete cover over the reinforcing steel, but this factor remains the greatest undefined issue.

4. In general the buildings can reasonably reach compliance with the ACT Multi-Unit

Housing Code. The biggest issues are internal alterations or reclassification for undersized dwellings, including the amalgamation of the two units on each floor of the Bedsitter Flats, provision of Ground Floor access units in the Owen Flats and Bedsitter Flats buildings, increased size for upper balconies in the Owen Flats, new external balconies for the Bedsitter Flats and reconfigured courtyard walls for private open space across much of the Precinct.

5. Compliance with modern Codes means it is highly unlikely that the 1960s clarity of

the Precinct, as illustrated in photos by Max Dupain, can be realistically and reasonably recaptured.

6. The requirement for some form of external private courtyards means it will be

practically impossible to totally recapture the pattern of generous open, shared landscape spaces between buildings that was a fundamental characteristic of the Post War International Modernism adopted by Sydney Ancher and NCDC for the original Precinct.



7. The existing mature landscape across the entire Precinct needs to be modified


8. Conservation and upgrading of the various buildings can take place within the

existing building envelopes, as illustrated in Options One and Two. The resultant accommodation is still generally quite small across the Precinct, when compared with contemporary multi-unit housing projects in prestige addresses.

9. An alternative model (Option Three) was developed to test the heritage implications

of augmenting the accommodation in most dwelling types.

10. As a result of the Housing Code compliance requirement to amalgamate units within the Bedsitter Flats buildings, Options One and Two result in a slight decrease in the total number of dwelling units on the Precinct.

11. Cost estimates indicate that the required conservation and upgrade works across the

entire Northbourne Housing Precinct will be in the order of

• Option One $21,720,300 • Option Two $28,773,150 • Option Three $41,526,300

12. The cost estimates have been prepared on the basis that the works are generally

undertaken in a comprehensive manner.

13. The total accommodation yield of the conservation scheme is 157 dwellings, slightly less than that existing now due to the required amalgamation of units within the Bedsitter Unit buildings. By contrast, the 2014 Master Plan yields in the order of 1099 dwellings.

14. Market value of the Precinct, if it is heritage listed and must be conserved is

$15,100,000. This is significantly lower than the $70,340.000 generated if developed to the highest and best use, as demonstrated in the 2014 Master Plan. The scale of this difference is magnified if other economic benefits to the ACT Government derived from taxes and construction activity is included.

15. The Precinct was developed as a single entity by NCDC in the late 1950s. The highly

distinctive and important unity of expression and presentation in architectural and civic design, urban planning and landscaping terms was only achieved by the strong overall project coordination and implementation imposed by NCDC. Accordingly, this report assumes that a similar level of conservation and repair standards and coordinated project implementation requirements would be imposed for an upgrading programme as was developed for the 2014 Master Plan for comprehensive redevelopment.

9.3 Heritage Impact Assessment

1. The impact on the overall heritage significance of Northbourne Housing Precinct arising from the proposed Essential Conservation Options (One and Two) will generally be positive in heritage terms. All of the features intrinsic to the heritage significance of the Precinct are essentially retained and upgraded.

2. The major negative external architectural impacts are confined to the Owen Flats and

the Bedsitter Flats Buildings from the alteration to or addition of the upper level balconies. To a lesser degree the Karuah Flats and Paired Houses will also be impacted externally by the upgrading of the balcony balustrades.



3. Internally, while Option One retains and protects a greater extent of the internal

character, Option Two with its minor internal demolition and upgraded kitchens and bathrooms can be readily regarded as a positive outcome in heritage terms. Both adopt mainstream approaches to the conservation and upgrading of historic houses.

4. The general upgrading of the landscaping, reconstruction of pergola network and

redesign of external privacy walls to courtyards will also result in a positive heritage outcome, although the clarity of the original network of shared open spaces between the Paired Houses in particular cannot be recaptured. This prevents the full recapture of the Post War International Modernism urban planning ideals embodied in the original project.

5. Potential impacts on those features of the Precinct that are intrinsic to its significance

are generally positive, with the exceptions noted above for the Owen and Bedsitter Flats.

9.4 “Feasible and Prudent” Alternative

1. In heritage terms, conservation and upgrade works (Options One and Two) have the capacity to protect, recapture and enhance the fundamental aspects of the heritage significance of the Northbourne Housing Precinct. They have a positive heritage result in relation to the features that are intrinsic to that significance. Accordingly, in heritage terms, this approach can be regarded as a “Prudent Alternative”.

2. In broad economic terms, conservation and upgrade to code compliance (Options

One and Two) come at a considerable construction cost and generates minimal market return. Accordingly, they cannot be regarded as a “Feasible Alternative”.

3. Option Three, which generates extensive augmentation of the existing buildings, is

not considered to have a satisfactory outcome in heritage terms, given the widespread intervention internally and the extent of the external alterations and additions.

4. Option Three had been developed as part of the 2010 Master Plan, at which time it

was combined with a major residential redevelopment of the overall Precinct. However, as a stand alone project, the resultant overall yield of total dwellings is not significantly larger than the existing. This makes it hard to justify the additional work and the loss of architectural and urban planning integrity in heritage terms. Accordingly, no formal market valuation was undertaken for this option.

5. Option Three, in its own right, is not regarded as a “Prudent or Feasible Alternative” in

heritage terms.



9.5 Relationship with the Griffin Plan As set out in Attachment 11, The 1959 Northbourne Avenue Housing Precinct, designed by Ancher Mortlock & Murray, established a significant difference to preceding residential developments in terms of the use of a variety of building types and group layouts, and by its confident adoption of Post War International Modernist expression. Its location on Northbourne Avenue was challenging given the ascribed importance of the thoroughfare. It was a site that required high quality civic design, as it straddled Northbourne Avenue, providing an important visual entry at the very northern extent of Canberra’s urban settlement at the time. The original design brief specified 150 single and paired houses, terraces and flats ranging from one to three storeys, arranged in groups of approximately 50 units and complete with car ports and driveways. This bore little relationship with the Griffins’ original intention of the main avenues boasting long views with ‘contiguous terrace buildings and small (fine grain) blocks with rear service lanes which have the highest proportion of individual tenancies to public street frontage.’ The completed Precinct comprised: four, four-storey bachelor flats; two storey Paired Houses; four, three-storey flats; five, three storey maisonettes, and Garden Flats. The urban planning and arrangement of different building types was such that the Griffins’ plan of the highest proportion of individual terraced buildings addressing the public street frontage was not possible. The original project brief for upwards of 150 dwellings and Sydney Ancher’s scheme did however respond to the spirit of Griffin’s intention for increased urban density and mix of land uses along the grand avenues By virtue of its location, extended frontage and the four storey point blocks created at the northern end, the Northbourne Housing Precinct accords generally with the Griffins’ idea of the Avenue as a gateway transition to the heart of the city with sweeping vistas along the length of its axis. Griffin also endorsed the use of nature strips and the planting of ‘grandly scaled rows of broad-canopy trees…The absence of front fences…allows house, garden and streetscape to merge as a continuous, park-like environment.” Griffin’s plan endorsed buildings along the main axes with a visual consistency of modest scale. While the Northbourne Housing Precinct deviated from both the Griffin ideals and the reigning medium density planning models of Canberra’s post-war period, the diversity of cubic building forms was mitigated by the consistent use of a monochromatic external colour scheme, a limited palette of materials and consistent use of design features such as floor to ceiling glazed panels. What remains in the main layout of Canberra today are Griffin's axes, elements of his street pattern, and a modified version of his lake system, and “to this has been added a minimalist steel outline of Griffin's central architectural concept, the pyramidal Capitol.” With so many of the primary elements of the Griffin Plan for the whole of Canberra pared back or stripped completely over the intervening decades and the emergence of different architectural and planning philosophies, it was inevitable that the development of the Northbourne Housing Precinct would only generically reflect the Griffins’ plan for this main avenue. The “Prudent” Alternative developed as part of the current assessment, known as Option One, retains and protects the essential architectural and planning features of the original estate as they made some, albeit limited, reference to the Griffin Plan.



10.0 Attachments

Attachment 1 Letter from ACT Heritage Council, dated 29 July 2014 with regard to the Heritage Impact Assessment of the proposed demolition of the three Dickson Bedsitter Flats on Blocks 40-41 Section 6 Dickson (DA 20142588)

Attachment 1a Letter from ACT Heritage, dated 3 July 2014, reference 2014 Master Plan, requesting more information before a formal evaluation could be made

Attachment 2 Detailed BCA compliance review of the five existing building types in Northbourne Housing Precinct

Attachment 2a Supplement to BCA Review - Acoustic report on Owen Flats

Attachment 2b Supplement to BCA Review - Acoustic report on Dickson Bedsitter Flats

Attachment 2c Supplement to BCA Review – Sprinkler Installation design, Owen Flats

Attachment 2d Supplement to BCA Review – Sprinkler Installation design, Dickson Bedsitter Flats

Attachment 3 Detailed ACT Multi-Unit Housing Code compliance review

Attachment 4 Architectural analysis of Option One

Attachment 5 General Structural Condition Report Dickson Flats

Attachment 6 Concrete Slab Core Sampling Dickson Flats

Attachment 7 Architectural analysis of Option Two

Attachment 8 Architectural analysis of Option Three

Attachment 9a Option 1 Cost Summary

Attachment 9b Option 2 Cost Summary



Attachment 9c Option 3 Cost Summary

Attachment 9d Option 1 Cost Breakup

Attachment 9e Option 2 Cost Breakup

Attachment 9f Option 3 Cost Breakup

Attachment 10 Comparative Market Valuations

Attachment 11 Relationship with the Griffin Plan

“feasible and prudent” heritage...

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