Timber Cladding in Scotland
HOMEGROWN NORWAY SPRUCE
VAN MIDDEN HOUSE
GOKAY DEVICI ARCHITECTS
Designed and constructed as a result of a research programme on 'Affordable Housing Projects' at The Robert Gordon University, the Van Midden house prioritises affordability and ecological sustainability and demonstrates that truly 'affordable' housing need not be inconsistent with good, responsible, sustainable design. The basic design concept rests on the cost savings which arise from the utilisation of a simple geometric plan form to maximise the space/envelope ratio. Further savings were achieved by centralising the living space thereby minimising the circulation and by using a simple modular structure.
The structure and cladding materials are predominantly of timber construction, and the resultant savings in weight also considerably reduced the cost and work involved in the substructure. Lightweight timber 'I' beams were used for the wall and roof members, a strategy which permitted the inclusion of 220 and 300mm thick recycled newspaper insulation in the walls and roof respectively and helped reduce the house's energy requirements to a minimum. The wall cladding is homegrown Norway spruce and this lightweight and very cost effective cladding material - used in combination with lightweight corrugated steel roofing - further reduced the construction costs. The house has deeper than normal eaves in order to shelter the external cladding.
Materials throughout the six-bedroom house were selected for their low embodied energy and, wherever possible, recycled materials were used (the majority of the materials were sourced locally, with the embodied energy estimated at 1.4GJ per square metre compared to 6.5GJ per square metre for a traditionally-constructed dwelling). By using a breathing wall construction, the need for vapour barriers has been eliminated. The wall and roof panels were designed to be prefabricated and with a trussless roof structure employed, the resulting space was freed-up to provide additional storage and play space.
In the context of external timber cladding this house is notable both because it uses lightweight timber cladding and structure as part of an integrated design approach, and because the cladding is made from Norway spruce. In common with standard practice on the west coast of Norway there has been no attempt to remove the sapwood and the timber has not been preservative-treated. The cladding, however, is carefully detailed to promote drainage and ventilation and has been given a water-repellent surface coating. This approach suggests considerable potential for the use of homegrown sitka spruce and although there are many uncertainties which require further research, this cladding market could be attractive to Scottish sawmills in the future.