SUSTAINABLE RETROFIT IN THE MELBOURNE CBD: CONTEMPORARY

PRACTICES.Sara J Wilkinson

Overview

• The context and rationale• The policy environment• Existing buildings and sustainability• Retrofit issues • Research aims and methodology• Results and interpretation• Where to next …………………..

The context and rationale• Retrofit of the existing stock is essential to mitigate global warming. • Most stock has no consideration of sustainability. • Legislated in the BCA in 2006. • In 2005-6 commercial buildings were responsible for 53% of all

greenhouse gas (GHG) emissions in the Melbourne CBD (City of Melbourne 2008).

• 87% of the stock we will have in 2050 is already built.

The policy environment• Is changing.• Melbourne 2020 - 1200 Buildings.• Sydney 2030 and others …..• Melbourne 2008 – 1800 commercial building Arup report 38%

reductions possible.• Sustainable Melbourne Fund – Environmental Upgrade Agreements

(UEAs).• Mandatory Disclosure 2010 – 2000m² + NABERS rating required.

Existing office buildings and sustainability

Existing office buildings and sustainability

Existing office buildings and sustainability

Retrofit issues

• economic, location and land use, physical, legal, social and environmental

Research aims• To gain a deeper understanding of the

sustainability improvements made to existing office buildings in the 1200 Buildings Program in Melbourne, Australia.

• To undertake a comparison of current practice to identify similarities and differences to retrofits in the 1200 Buildings Program.

Research methodology• Study involved the analysis of words to examine practices regarding

sustainable commercial retrofit in the 1200 Buildings Program. A quantitative approach was unsuitable - too few events (Silverman, 2000).

• Exploratory research to identify what is undertaken was achieved through a content analysis of completed projects. (10 projects).

• Interviews provide deeper and richer data - not possible to trace all those involved.

• Case study can be exploratory or explanatory (Robson, 2003). The analytical strategy is partially explanation building and partially pattern matching to previous patterns of building retrofit practices in the Melbourne CBD.

Results and interpretation

Figure 1 – Case study building age and address.

Age (years)

Case

Objectives

131 Queen St Make safety and essential services code compliant.Achieve to a 4/ 4.5 NABERS rating.Reduce running costs.

636 Bourke St Develop an environmentally efficient building in the use of energy and water.Minimise noise transfer in and around the building.

247 Flinders La

Achieve a minimum NABERS 4 star.

490 Spencer St

Create a zero GHG building

500 Collins St Achieve A-grade building.Attain high environmental efficiency.Maximise tenant retention during upgrade to maintain optimum cash flow and provide pool of long-term tenants.Elevate tenancy profile by increasing the average size of tenancy, length of tenure and quality of tenant achieve a justifiable ROI.

406 Collins St Improve energy efficiency.Achieve a 4 star NABERS energy rating.Reduce carbon footprint and use green power sources.

182 Capel St Reduce carbon footprint. Reduce carbon emissions by at least 50%.Attain a 4.5 star NABERS Energy

115 Batman St Introduce state of the art engineering services with very low levels of energy consumption.Provide comfortable working environment to enhance productivity Achieve 5 Star Green Star and 5.0 star NABERS Energy ratings.

385 Bourke St Achieve 2.5 NABERS Energy rating. 530 Collins St Achieve a 4.5 star NABERS Energy rating.

• 70 measures were implemented. • Environmental and social. • Many environmental measures implemented due to potential economic

benefit. • Most measures, 61%, related to building services. • 73% related to energy efficiency. • Water economy measures featured less (11%). • Measures to fabric were associated with energy efficiency - less frequent

(17%), involve access challenges, disrupt occupants, and are expensive. They offer a longer term solution than upgraded services which require maintenance and are replaced within 20 years.

• Social sustainability featured in 4 cases (amenities provided to users in respect of improved IEQ).

• 6% had a social sustainability component. (a roof top garden for social space, however rationale included environmental benefits of reducing the UHI effect, insulating the roof and reducing energy use (economic benefit). One project featured housed small businesses driven by social justice and equity issues; having a positive social sustainability contribution.

• Overall social sustainability has a lower profile.

Physical issues - not related to fabric performance though acknowledged as important the costs are higher. Reflects the current economic climate and timeframe for ROI. Other physical factors were hostile factors such as construction noise disrupting tenants in situ.

Economic objectives were met in many cases with energy and water costs reduced, maintenance costs reduced in all but one case, higher rents recorded and yields achieved. In two cases there were concerns regarding ROI and these projects relied on Green Building Grant for viability.

Environmental outcomes were achieved and exceeded in some cases NABERS ratings exceeding targets. Energy and water use was reduced in all cases and one is zero carbon on sunny days.

Social outcomes positive with higher productivity and improved IEQ measured in one POE. Staffs were ‘happier’ in the post retrofit buildings. Green roof worked well and the hotel building attracted some on the basis of ‘green’ credentials.

Management issues were difficulties of getting multiple owners to agree, the need to communicate effectively with and educate tenants, the need for strong PM, the need for advocates to promote ESD and for independent commissioning agents to verify data. Retention of tenants was positive. In some the aim to increase occupancy was achieved.

More generally;Owners motivated by different drivers; predominant initiating party was BE consultants.

Fringe locations featured more prominently compared to general trends and earlier studies (Wilkinson 2012) however low prime is where most retrofits occur and this compliments earlier study and general practices.

In the 1200 Building Program preference is for non-heritage buildings confirming the additional requirements for adaptation may deter owners from adapting. Ungraded buildings were most likely to be retrofitted (50%), followed by B grade (20%) -1200 Buildings Program is reaching all grades of stock which is vital if all stock is to be adapted.

Substantial improvements afforded in terms of energy efficiency. Snyder’s (2005) finding that there is a relationship between proactive legislation and change in the adaptation market is supported; here the realisation is buildings with enhanced sustainability.

Thank you for listening – any questions?