Patch Elm Lane, Gloucestershire

2024 RIBA South West & Wessex Award

Patch Elm Lane, Gloucestershire
Mitchell Eley Gould for Veya Homes
Contract value: £1,400,000
GIA: 496 m²
Cost per m²: £2,822

With these four new houses in South Gloucestershire, the developer client has shown that well-designed, low-carbon housing can be built at a viable commercial cost. The architects worked with the developer over a five year period to develop a modular timber system that offers more flexibility than typical prefabricated panel systems. To add to the challenge, the team tried to source materials from within the UK and as close to the site as possible. The project is actually a way of thinking, a body of research and the development of a system, of which the houses at Patch Elm Lane are the first fruits.

All four houses have the same rectangular plan, with living spaces on the ground floor and three bedrooms on the upper floor. The ground floors have a large kitchen/dining space at the rear and smaller living room at the front, which can be used for different functions as the rear room is big enough to also make a sitting area. Two houses are detached and two semi-detached, laid out around a well landscaped shared front driveway with enough parking to avoid cars spilling on to the lane. Each house has a storage shed for bins, bikes and garden equipment, placed to divide off and provide privacy for the generous rear gardens that overlook fields behind.

The client’s roots are as a shop-fitting and joinery company with a workshop and skilled craftsmen experienced in precision prefabrication, allowing them to experiment with prototypes as the design developed. The wall system consists of storey-height, 1.2 metre wide, closed-cell softwood timber frame panels filled with sheep’s wool, made on site to make transportation more efficient. C24-grade spruce was specified as this is available from a UK source. Often in highly insulated buildings the timber frame ends up being thicker than structurally necessary to contain the thickness of insulation required, but here a similar thickness of wood fibre insulation is added, allowing the structural timber to be thinner. Engineered timber joist floor cassettes are hung between the walls and trussed rafters make up the roof structure. Thermally modified ash from a local timber merchant has been used for the external cladding.

There is an obvious respect and collaborative relationship between architects and developer. The construction methods are not new, but the ambition and determination to fine-tune the system, open up supply chains and find local product sources is inspirational. The design goes beyond energy calculations to really understand the impact of materials sourcing on the carbon profile and sustainability of the scheme. The result is an excellent measured energy use of 28 kWh per square metre per annum and cradle to grave embodied carbon emissions of 143kg of CO₂ equivalent per square metre.

This is a highly successful pilot project. It will be interesting to see how it might be replicated as a model on a larger scale and with smaller homes affordable to a wider demographic. The ultimate ambition would be the mainstreaming of such solutions into the wider construction industry.

See the rest of the RIBA South West & Wessex winners here. And all the RIBA Regional Awards here.

To see the whole RIBA Awards process visit architecture.com.

RIBA Regional Awards 2024 sponsored by EH Smith and Autodesk