speckled wood - fastly · swan barn farm, surrey. building design guide extension of base camp to...

Swan Barn Farm, Surrey

Building design guide

Extension of base camp to provide long-term volunteer accommodation July 2012

n materials sourced from the National Trust Estate

n volunteers involved in construction

n labour partly in-house by the Black Down Countryside Team, South Downs

n environmental improvements to existing building

Speckled Wood

BackgroundSpeckled WoodSwan Barn Farm, Surrey

Above The old shed before it was demolished to make way for Speckled Wood

Swan Barn Farm is located on the eastern edge of Haslemere. It covers 29 hectares of grazed pasture, hay meadows, common land, woodland, hedgerows, streams and ponds.

The area is well used by the local community who value the beautiful countryside on the doorstep of Haslemere town centre, on the edge of the South Downs National Park. The site is open access with an extensive footpath network.

Swan Barn Farm is home to the Trust’s Black Down Countryside Team. From their base at Swan Barn Farm the Countryside Team manage hundreds of acres of woodland, heathland and meadows. The woodlands on the Estate are managed primarily for public access and nature conservation. Large areas are managed as traditional coppice. The cyclical cutting of coppiced woodland offers ideal conditions for a wide range of woodland wildlife as well as providing timber for use on the Estate.

The site is also home to the Hunter Base Camp, named after Sir Robert Hunter, one of the founders of the National Trust, who once lived in Haslemere on the edge of Swan Barn Farm.

Hundreds of volunteers from across Britain stay at this base camp each year spending their time working on nearby countryside sites providing access and nature conservation benefits to the surrounding landscape and community. They take new skills and knowledge, and a sustainability message home with them.

The need to upgrade facilities at the Hunter Base Camp had been discussed for a number of years.

2Speckled Wood | Swan Barn FarmBuilding design guide

Background

Above Hunter Base Camp and shed before the project started

The new building would be called ‘Speckled Wood’ – named after the well known woodland butterfly which frequents the woodland glades and coppices created as a result of the provision of materials for the building.

The base camp was expensive to run. It used to have its heating and hot water supplied by electric storage heaters and an electric immersion hot water cylinder. This was a really difficult system to work with, the heating only warmed up over night so it could not be turned on when it was needed. This meant it had to be left on much more than necessary just to ensure the place was habitable, it consumed huge amounts of electricity.

The team at Swan Barn Farm were all keen to see this change. The need to ‘green’ the base camp was identified – to introduce energy efficiency measures and alternative sources of renewable energy.

At the same time, the need for new long term volunteer accommodation was identified as a way of developing the availability of volunteering opportunities at Swan Barn Farm.

The Countryside Team had been assisting on a roundwood cruck frame project in the local area. The Head Ranger realised that a similar roundwood cruck frame structure could be used to extend the base camp facilities to provide extra volunteer accommodation. The necessary materials were already widely available on the Black Down Estate. This type of project would also provide an opportunity for volunteers to get involved and learn woodworking skills.

The team wanted the new building to reflect the landscape and to be constructed from materials sourced on the Estate in an environmentally-friendly manner.

A consultant/contractor was approached to develop the project and design. With an established roundwood frame business he was able to provide an overview of the process from start to finish.


Project brief

Above Raising the roundwood cruck frames

This project was established to achieve the following objectives:n Extend the base camp to provide accommodation for long term volunteers;

n Introduce energy efficiency measures to the new and existing building to address unsustainably high energy and running costs;

n Demolish the redundant shed (to the left of the base camp);

n Provide an opportunity to demonstrate the construction of a building using sustainably sourced local timber from National Trust woodland.

The concrete-based, single-storey wooden shed at the end of Hunter Base Camp would be replaced with a two-storey cruck frame building, no larger than the current footprint of the existing shed. The new building would be linked to Hunter Base Camp at ground floor level.

In order to accommodate long term volunteers at Swan Barn Farm, the existing base camp had to be extended. The new building would become an exemplar of environmental sustainability and an integral part of the project as a whole.

The project was developed with consultation and support from a local designer and woodsman. The designer/woodsman was commissioned to design an environmentally friendly, locally sourced building which could be constructed with the help of volunteers.

The new building would be constructed using a roundwood timber frame. This construction technique produces attractive, functional buildings that can be sourced from the local woods. Exterior walls would be made of straw bales, rendered with lime or protected with oak boards. Interior walls would be of wattle and daub with earth plaster and the roof of chestnut shingles.

Environmental improvements to the existing base camp building would include the installation of additional insulation, draught-proofing, secondary glazing and LED lighting.

As part of the improvements project at Hunter Base Camp, the old environmentally inefficient and costly storage heaters would be replaced by a new log-fired biomass boiler, which would heat and provide hot water for both the new and the existing building.

A solar powered hot water system would be installed for use in the summer. In addition, solar panels on the roof would generate electricity; these would complement the new insulation and secondary glazing to make both buildings as environmentally friendly as possible.

There was little point constructing an eco-building next door to a base camp that was wasting carbon.

100% of space and water heating and a significant proportion of lighting, appliances and cooking energy requirements would come from renewable sources.


Project brief

Above Architect’s drawings for the Planning application

With much of the woodland managed through coppicing there is an abundant supply of wood on the Black Down Estate, making this the obvious choice for the fuel supply. It is sustainable, renewable and by helping provide an end use for the coppiced timber, has a positive effect on local wildlife.

The availability of volunteers to cut, transport and stack timber also makes this an economically attractive method of heating both the base camp and the new long term volunteer’s accommodation.

Key factors The new structure would be sustainable and environmentally friendly, built of locally sourced materials. Volunteers would be involved in the construction as an educational experience where the process of construction would itself be a way of explaining and demonstrating the coppicing and countryside management work undertaken in the surrounding area. Participants would be able to walk to see where the wood for the building originated, see it harvested and processed.

The woodlands at Swan Barn Farm and on the wider Black Down Estate contain suitable species for the construction of roundwood timber framed buildings.

The new building would provide free accommodation for up to three people who, in return for accommodation, volunteer on the countryside estate managing local landscapes, learn new skills and embark on a career in conservation and environmental education.

This project hoped to develop the potential of Swan Barn Farm as a sustainable education centre for countryside management. For example, by making better use of the site, enhancing the existing base camp, improving and expanding the environmental experience of users and engaging more fully with the local community.

The assistance of long term volunteers based on site would be central to realising these goals.

Consultees n Architectural Panel n Blackdown and Hindhead Supporters Committee n Haslemere Town Council n Neighbours n Surrey Hills AONB n Transition Haslemere n Visitors n Waverley Borough Council, Planning authority


Site issues

Left Harvesting wood for the building

The team did not feel that the project proposal would have any adverse impacts on the quality of the landscape or the character of the AONB. They felt that the project would significantly assist with the conservation and enhancement of the natural beauty, and landscape character of the surrounding area including its distinctiveness and diversity.

DesignationsThe following designations apply to this project:n Greenbeltn Area of Great Landscape Value (AGLV)n Surrey Hills Area of Outstanding Natural Beauty (AONB)

Design approach

The design of the building is based on roundwood timber framing. This utilises small diameter round wood poles and draws on techniques from traditional sawn timber framing.

The size of the building was determined by the existing footprint of the dilapidated shed. Although the veranda falls outside of this footprint.

The only materials not produced on Trust property were the straw bales which came from a local farm.

A pond would be created adding to the biodiversity but also to provide a source of clay for the hazel wattle and daub walls.


Design approach

Top left Applying the shingles

Bottom left Staff from Polesden Lacey Hub making shingles

The following summarises some of the design challenges that were encountered through the design process:

n Structural Engineering calculations for the roundwood cruck frame were needed to satisfy Part A of the Building Regulations

n There was no data for Fire Regulations. An earlier precedent had to be used for fire testing

n Calculations to confirm the U-value of the walls were undertaken to satisfy Part L of the Building Regulations

Adaptation and re-useConcrete from the storage shed previously on site has been recycled and provides part of the footings for the new building.

Engagement There has been a great deal of community involvement in this project from the start.

n A community meeting held by the National Trust to explain the purpose of the project was fully booked, demonstrating a high level of interest from local residents.

n The Planning application received extensive local community support and was delegated to officers to approve.

n Local people raised funds for the project through sponsorship of trees in the new orchard as well as by sponsoring shingles for the roof.

n About 100 local people came to watch the raising of the main frame from the field adjacent to the building.

n Public events and tours of the site were very well attended.

n 685 volunteers gave 4,074 hours to produce 14,863 handcrafted wooden shingles for the roof.


Design approach

Above Testing the new log burning stove

Engagement Media coverage n BBC Countryfile (23 October 2011)

n A number of stories in the local press including a full page spread in Haslemere Herald

n Presentation to Rudgewick Preservation Society on the project

Public events and special projects as a result of the facilityn Green Wood Working Day and Speckled Wood Grand Opening (summer 2012, but Green Wood Working Day will now be an on-going annual event)

n Community Apple Pressing Day (now planned to be annually in autumn)

n Wassailing in Speckled Wood Orchard (January 2013)

n Heritage Open Days as part of English Heritage Scheme (Autumn 2012)

Public accessn There was continuous informal access as this is an open access site. Visitors frequently came to see how the building construction was progressing and now they come to see it completed.

n Hundreds of National Trust Working Holiday Volunteers stay in the adjacent base camp and work on the site each year.

n Tours are frequently given of the buildings and explanations of the project provided to interested groups and parties.

Environmental CEN Services Ltd. assessed the potential for environmental improvement at Hunter Base Camp. Their objective was to appraise energy efficiency and renewable energy options. The conclusion was that the energy performance of the building was poor with electric heating and little insulation.

Proposals included the installation of a log batch boiler, a separate 5kW log stove in the new building, solar thermal panels for hot water heating and photovoltaics for electricity, a new wet central heating system (radiators), secondary glazing and improved insulation.

It is anticipated that 7,615 kg/annum CO2 will be saved through the implementation of the proposals. Prominently displayed meters will show how much energy has been generated by the photovoltaic panels. Energy cost reductions at the base camp will then increase funding available to the Trust for conservation work in the area.

The walls of the new building were constructed from straw bales. These perform significantly better than the minimum requirement.

The roof and floor have been insulated with environmentally friendly, natural sheep’s wool insulation. This has a higher thermal conductivity than many of the more high tech insulants available, but has a significantly reduced carbon footprint. The use of expanded polyurethane insulation of the same thickness would result in much improved U-values but is not considered appropriate in a building which endeavours to minimise impact on the environment by using locally sourced, natural materials with a low embodied energy.

Hunter Base Camp is situated on a north facing hillside, with the large pitched roofs facing almost due north/south. The roofs are generally unshaded and the south facing roof slope is ideally suited to the provision of photovoltaic panels and solar thermal panels. The south facing roof slope, being at the rear of the building, and shielded by woodland along the boundary, is largely hidden from view, thus minimising the visual impact of any solar panels.


Design approach

Top right Strawbale walls

Bottom right First coat of lime plaster on the strawbales

Nature conservationAn ecological assessment was carried out in July/August 2010.

There was no evidence of bats found within the dilapidated shed, although there was evidence of bats using the main base camp building. The report made a number of recommendations to mitigate any potential harmful impacts of the proposals, including the timing of the works.

A bat access tile was installed high on the base camp barn roof near the ridge at the south-east end. This was to provide an alternative access for bats using the loft space that might otherwise have been lost to the construction of new roofing joining the barn to the new building.

The design makes provision for an alternative access for bats using the loft space within the base camp in accordance with the recommendations of the biodiversity assessment.

n General Managern Project Managern Building Surveyorn Rural Surveyorn Curatorn Environmental Advisorn Land Use Planning Advisorn Consultant Ecologistn Contractorsn Architectn Supporter and fundraising assistant

Project team


Construction

Top left Riven chestnut laths

Bottom left Rafters in place

The buildings on site included the main barn (base camp) and adjacent tool store, a small office for the Countryside Team and a workshop and tool store.

The base camp building covers approximately 126m2 and contains three dormitories, a lounge, kitchen and toilets. The adjacent shed was mainly used for storing tools.

Materials Materials were sourced from National Trust Estates.

Foundations are of local stone and recycled concrete from the former shed.

The roundwood cruck frame is made from coppiced sweet chestnut.

Coppiced sweet chestnut was also selected for the roofing shingles.

Douglas fir was used for the wall plates, floor joists, rafters and battening.

Oak was milled using a mobile saw mill and was used for the floorboards and cladding.

The walls were made of straw bale or lath and plaster.

Sheepswool was used for insulation.

The roof was covered with over 14,000 shingles which were handmade by volunteer groups.

People The building was constructed in close association with a local woodsman / sustainability and woodland management writer along with the Roundwood Timber Framing Company which was the main contractor for the build.

An architect specified internal finishes and window frames. The specification developed during the process.

Labour was partly from the Roundwood Timber Framing Company and partly in-house by the Trust’s Black Down Countryside Team and Volunteers.

On-going maintenance will be managed mostly in-house with contractors where necessary.


Construction

Process The construction of the building took place in a number of stages: n The existing shed and the asbestos roof were removed by the contractor;

n Concrete from the existing building was crushed with a mobile crusher and compacted into 1m3 foundation pits. These were capped with a slab to form foundations;

n A framing bed was constructed and the main chestnut cruck frames jointed and raised. A ridge pole, wall plate, under-floor supports, jowl posts and wind bracing were added to form the main frame. The frame was traditionally jointed with oak pegs;

n Rafters span from the wall plates to the ridge pole. These were covered with a waterproof membrane, battened, counter-battened and then shingled. The roof is insulated with sheep’s wool;

n The floor joists which span the width of the building were noggined. They support a 21mm tongue and groove oak floor above and 9mm panel vent breathable board beneath. The cavity between them is also insulated with sheep’s wool;

n The external walls were constructed with locally sourced straw bales and lime plastered to both faces. The internal face was finished with several coats of limewash;

n Internal walls were constructed with traditional wattle and daub;

n A timber spiral staircase was hand made to provide access to the upper floor and bedrooms.

Above PV and Solar Thermal installations

The building measures approximately 10m x 5.75m. There is a link passage connecting it to the main base camp building.

Water supply and sewerage are provided from the existing base camp building.

The access road to the parking area at the rear of the base camp has been slightly realigned –approximately 1m to the west. No additional parking provision has been made.

Solar 13 Schüco MPE 215 PS 05 EU photovoltaic modules have been installed on the south facing roof slope of the base camp building. These provide electricity for use both in the base camp and the new volunteer accommodation.

Four flat plate solar thermal panels on the same roof slope provide hot water to new accumulator tanks.

These collect the suns energy and focus it on a pipe run containing an anti-freeze solution. This solution passes along a pipe into the base camp plant room where the heat is exchanged inside a cylinder to heat the domestic hot water supply. When the sun is not providing enough heat the system is boosted by a feed from the biomass boiler.

The photovoltaic panels were installed on the top half of the base camp roof. The solar hot water panels are on the lower section of roof. The panels are fitted to bars which attach to brackets that reach through the tiles on the base camp roof and attach to the rafters. The local bat worker was present for the installation. He ensured that any disturbance to the roof did not cause any problems for the local bat population.

The base camp sleeps up to 19 people, with a further three in the new building, leading to quite a demand for hot water. The solar and biomass systems have been scaled to cope with this demand.


Construction

Biomass A 40kW Fröling log batch boiler sits in the link between the new and existing buildings. The boiler also supplies hot water to accumulator tanks which serve a new central heating system for both buildings.

A log fired system was selected because it means the fuel has the minimum of processing and machinery involved in its production. It is fuelled by coppiced sweet chestnut from the Estate just half a mile away.

The boiler has three sections. The logs are loaded at the top, the middle section is for lighting (although the system also has automatic ignition). The bottom section is the gassification chamber, where all the smoke and products of combustion are circulated and re-ignited to make the boiler extremely efficient.

The boiler self-regulates the flow of air to ensure the most efficient combustion possible. It then heats the water in a heat exchanger at the back. This hot water is the stored in two large super-insulated thermal storage tanks. The tanks store the thermal energy from the boiler. A system of pipework and heat exchangers take the heat from the stores and distribute it to the radiators throughout the base camp and Speckled Wood, as well as to all the taps, baths and showers.

The thermal stores have a second feed from the six solar hot water panels on the base camp roof. On a sunny day they should keep the thermal stores topped up without the need to burn any wood. During the rest of the year they reduce the need to feed the boiler.

The firewood used to warm the buildings at Swan Barn Farm is all produced as a part of the sustainable management carried out in the Trust’s local coppice woodlands, and as such is a very environmentally friendly way of keeping warm.

Above Inside the boiler

Productsand services

The Roundwood Timber Framing Company Ltd.Prickly Nut Wood, Lodsworth, West Sussex GU28 9DRwww.ben-law.co.uk

Chartered Architect and DesignerThe Studio, 2 High Bank, River, Petworth, West Sussex GU28 9AX01798 860912 www.valerie-hinde.co.uk

Waterproof breathable membraneKlober Permo 01332 813050www.klober.co.uk

Boiler supplierEconergywww.econergy.ltd.uk

Boiler and Solar Panel InstallationA Greener Alternativewww.agreeneralternative.co.uk

PhotovoltaicsSchücowww.schueco.com


http://www.ben-law.co.uk

http://www.valerie-hinde.co.uk

http://www.klober.co.uk

http://www.econergy.ltd.uk

http://www.agreeneralternative.co.uk

http://www.schueco.com

Near right Speckled Wood and Hunter Base Camp from the rear

Far right Wooden pegs

Funding

n Black Down and Hindhead Supporters Committeen The Hamamelis Trustn Memorial benchesn Major Donors/Just Givingn Orchard sponsorship schemen Timber incomen Gift monies for Black Downn Community fundraising eventsn Three Counties Associationn Transition Town shingle sponsorshipn 14% of this project was funded externallyn 86% was funded by the National Trust

n Total cost: £188,087

This type of system is eligible under the Renewable Heat Initiative effectively paying back a grant over time as heat is generated.

The main on-going cost is in terms of wood and manpower, both for loading the boiler and for processing timber. This is a large wooded estate, and in effect uses what would otherwise be low value timber to run the system. As far as the manpower goes, the long term volunteers living in Speckled Wood help with the cutting and processing of firewood.

Procurementn Single stage tenderingn The architect was selected through the experience of working with the specialist consultant/contractorn JCT Minor Works

Project durationn Project proposals produced: September 2008n Construction start date: May 2011n Completion of project: May 2012


Above Verandah with vegetable beds

Post project review

Speckled Wood is an inspirational building which was constructed by the National Trust in association and collaboration with the local community. The building is constructed from materials sustainably sourced from local woodlands and is designed to echo surrounding landscapes. There is open access to the site as well as frequent events and tours of the building.

Speckled Wood is occupied by three long term National Trust volunteers who are training for careers in countryside management and education. It aims to inspire and educate communities about stewardship of their local environment.

The building has allowed the National Trust to significantly improve the sustainability not only of the base camp but also of Swan Barn Farm and other local sites.

Having long term volunteers living on-site has enabled:n The installation of a log fired biomass boiler to heat the residential buildings;

n The planting of an orchard of heritage fruit varieties;

n A small chicken run and flock;

n The development of a vegetable garden;

n A site beehive.

The products of these endeavours provide visitors and the local community with a demonstration of sustainable living which will hopefully inspire them to make positive changes in their everyday lives. A number of events are held on site every year which demonstrate the project, its aspirations and its results to the local community.

Without Speckled Wood the National Trust would not be able to offer long term training opportunities to volunteers at Haslemere nor would they be able to demonstrate sustainable land management and living as effectively.

Best practicesIn general the team are united in agreement that the building has been a success. There have been very limited maintenance issues to deal with.

The key measure of success has been the improvement in energy performance. With baseline data available from 2009 it has been possible to demonstrate the improvements in energy efficiency that have been made since the project was completed. In 2009 the electricity bill was approximately £2,980 this had reduced by £2,160 to approximately £820 in 2012/13. Renewables now account for 86% of the property’s energy. Swan Barn Farm’s fossil fuel consumption has decreased by 72% since the 2009 baseline. However, the total energy consumption including renewables has increased by 64%. This is not surprising, however, given that there is a new building with three permanent residents who had not been on site in 2009.

The shingles have been performing really well; the building is completely weathertight. Volunteer involvement in the construction works generated support and interest for the project – shingles were sponsored to help with fundraising, for example.

The heating system is performing well.

Speckled Wood has shown that it is possible to build using locally and sustainably sourced materials.


Above Community Open Day

Post project review

Best practicesVolunteer and community support Most important of all the people involved in the development and construction of this facility was the support and involvement of the local community. Groups of volunteers from all walks of life came and worked with the National Trust in the local woods making wooden shingle tiles for the roof. 685 volunteers gave 4,074 hours to produce 14,863 hand crafted wooden shingles. Without their assistance it would not have been possible to complete the roof on the building.

Groups of volunteers from a range of backgrounds helped with a number of construction tasks. Numerous local residents came to visit and watch on the day of the frame raising. Hundreds of further people have visited the site at various events and tours since the building was completed.

The project only really began with the completion of the building. The facility can now fulfil its purpose and function by providing a space for living and learning for long term volunteers as well as allowing the National Trust to demonstrate to various communities sustainable management of landscapes and sustainable living.

EngagementThe project has generated a lot of local support and interest, and also supported the development of volunteering opportunities at Swan Barn Farm.

Public events and special projects as a result of the facility:n Green Wood Working Day and Speckled Wood Grand Opening (now planned annually for Autumn)

n Community Apple Pressing Day (now planned to be annually in Autumn)

n Wassailing in Speckled Wood Orchard (January 2013)

n Heritage Open Days as part of English Heritage Scheme (Autumn 2012)

Public access:n Continuous informal access as it is an open access site. Visitors frequently came to see the building construction progressing and now they come to see it completed.

n Hundreds of National Trust Working Holiday Volunteers stay in Hunter Base Camp and work on the site each year.

n Tours are frequently given of the buildings and explanations of the project for interested groups and parties.


Right The link building and biomass boiler flue

Post project review

Best practicesWoodland managementThe majority of the construction materials were produced in sustainably managed woodlands or farmland within a two mile radius. Naturally durable timber from wildlife rich woodlands has leant the building a unique character which is intimately associated, and connected, with the local landscape.

The construction of the building from coppiced timber enhances local woodland management, habitats and public enjoyment of the area. The project assists the on-going management of the countryside in the area by facilitating the recruitment of long term volunteers who support management of the local countryside. The project also enhances opportunities for access to the local countryside and its conservation.

PhotovoltaicsThe photovoltaic system is capable of generating 2.2kW on an ideal sunny day, but will also do well even in less than ideal conditions. This size system is capable of producing enough green electricity to save almost a tonne of CO2 being emitted into the atmosphere per year. It should produce about half of the energy that would be required by an average UK household.

The panels produce DC electricity; this is changed by an inverter into the AC which is used. When electricity is being used on the site it will reduce the draw on the National Grid. When the electricity is not being used, the power produced will be sold back to the Grid, giving credit which will help pay back the cost of the panels.

The system came with a heat meter, which is also solar powered; it provides all sorts of information including what current is being generated, as well as information about how much CO2 and money the system is saving. It demonstrates that even on a fairly cloudy day the panels can generate 1.52kW.

The estimated energy yield from the photovoltaics is 2,340 kWh/year.

The renewable technologies have made these two buildings self sufficient in terms of their heating and hot water energy needs.

The energy efficiency measures introduced have produced real savings in energy costs, and presented very few maintenance issues to date. This will continue to be monitored.


Above The new window which was added into the kitchen at a later stage

Post project review

Lessons learntSpecification and design The windows were incorrectly specified. Rather than specifying off the shelf pre-fabricated frames, the team would have preferred to fabricate these locally using woodland material.

A few design changes were introduced during the process which had some cost and time implications:n An additional window was introduced, which required a small section of bale wall to be taken down.

n Sun pipes were introduced to the showers/toilets of the base camp building.

n The link building roof was adjusted to avoid a valley gutter.

n Rainwater harvesting had not been included for in the original costs.

n Additional landscaping work was needed which had not been costed.

Pre-construction processWhilst the design was well developed, the drawings were sometimes difficult for the team to interpret. Visualisations of Speckled Wood produced on CAD were a little too ‘crisp’ to give a fair representation of the aesthetic quality the building would have. It might have been useful to have had some 3D models or renderings. Implementation

Shingle roof constructionn Fabrication of the required 15,000 shingles took longer than expected. A shingle coordinator was appointed to ensure that sufficient shingles were supplied where and when required.

n The roof membrane had to be replaced after it was left out in the sun for too long.

n Volunteers/Working Holiday participants/Trust staff and consultants all assisted in the production of shingles – a significant amount of time and resource was required for this.

n A professional roofer was employed to oversee the fitting of shingles, most of which were put up on the roof by Trust staff and volunteers.


Above The staircase newel post is made from larch, the first and last three treads are elm, the supporting frame for the first couple of steps are oak, and the treads in the middle are all beech. The spindles and handrail made of chestnut

Post project review

Lessons learntImplementationTimber framen The material sequencing/cutting order seemed to change. It would have been better to have had a more organised cutting list/schedule.

n Moving materials from woodland to site was a logistical challenge and required significant resource and borrowed machinery.

n A fixed asset bid was undertaken to purchase a saw mill for use on the site.

Paintn A special primer had to be used on the windows because the eco paint would not adhere without it. This seemed to work and is holding up fine.

Walls n Straw bales were sourced from the neighbouring farm. These had to be re-baled into smaller straw bales, as they needed to be more compressed. It would have been better to have sourced bales that had settled for a year.

n The internal earth plaster did not work on the laths; it may have performed better on woven wattle. There may have been an issue with the earth-plaster mix proportions, as there had been no agreed specification.

n The walls ultimately had to be lime plastered. The team was taught how to do this by someone from the Roundwood Timber Framing Company Ltd.

Limecrete floor n The thickness of the floor in the link building was incorrect. This should have been specified to accommodate the load of the water storage tanks. Research for the specification should have been conducted earlier or designed using a structural engineer.

Renewables installersn It was difficult to find a reliable installer for the renewables.

Implementation and operation of renewable energy technologiesThe wood being used was initially a bit ‘green’ which affected the performance of the boiler. The team have now stockpiled sufficiently seasoned wood to supply the boiler.

It is important not to underestimate the manpower involved with this type of biomass system.

Flow control valves were fitted to the showers to ensure that the volume of heated water for the showers was controlled more effectively.

LED lights have performed well and are complemented by sun pipes in the wash rooms which have also worked well.


Near righ Speckled Wood interior

Far right The woven barrier on the first floor gallery is made from hand cleaved chestnut laths

Post project review

Lessons learntIssues following completion Rainwater harvesting n Rain collected from off of the shingle roof has some staining. This could be resolved by introducing filters.

Bat monitoring in base campn An Environmental Impact Assessment was undertaken. Solar panels installed on the roof and bat and swift boxes introduced.

Renewable Heating Incentive (RHI) n This process was quite onerous. It helped to find a point of contact at OFGEM.

Building Regulations:n The height of the handrail on the veranda had to be adjusted.

Sheep’s wool insulationn The policy on using sheep’s wool insulation is currently under review due to concerns with increased fire risk and moth infestations.

The following items had not been included in the original scope and therefore attracted additional cost and time:n Landscape changes;

n The base camp building had to be refurbished following re-wiring works.

RecommendationsAppoint a full-time Project Manager.

Make sufficient allowance for the human resource (time and cost) needed to harvest and produce building components.

Involve relevant consultants early in design and planning stages to ensure the brief is fully developed, and design constraints understood.

Create opportunities to involve volunteers in the project, and plan for it.

AwardsShort-listed for an RICS award – Community benefit category


Right Speckled Wood

Post project review

End-user feedbackLocal communityFeedback on the building has been overwhelmingly positive. People are very interested in the building and its construction techniques/materials. The Countryside Team is trying to use this interest to bring home a broader message about the sustainable management of the woodlands and landscapes. In addition they hope to use the project and the interest it brings to deliver a message and example about sustainable living and food production. The project has enabled the Trust to develop a vegetable garden, orchard, beehive and chicken run. Anyone attending an event at Speckled Wood gets the opportunity to go home with a taste of sustainable living and hopefully some inspirational ideas.


Further information

ContactSwan Barn Farm, Black Down Estate, Haslemere GU27 2HU www.nationaltrust.org.uk/swan-barn-farm

If you require this information in alternative formats, please telephone01793 817791or [email protected]

Case study information

Design by Inkcap Design.

Products and services: Use of products and services is not necessarily an endorsement by the National Trust.Copyright: National Trust retains copyright for this document.Please do not reproduce/photocopy without prior permission.

Building Design Guide concept devised by Rory Cullen and developed by Jonathan Howard, with acknowledgements to Jacky Ferneyhough, Ingrid Chesher and Angela Collins.

© 2013 National Trust. Registered charity no. 205846.

Above Speckled Wood with Hunter Base Camp in the background


http://www.inkcapdesign.co.uk

speckled wood - fastly · swan barn farm, surrey. building design guide extension of base camp to...

Documents