Timber Frame House_Bedfordshire_2_A-Zero Architects_BANNER.jpg
 
 
 
Timber Frame House_Bedfordshire_5_A-Zero Architects.jpg
 

When an old farm was subdivided and sold individual plots, the walls of an old cow shed and dairy became the starting point for a new dwelling for a young family.

The design brief was that the new build house should be an exemplar in environmental performance both in terms of operational energy and in terms of embodied energy, whilst at the same time achieving a tight budget.

 

The design was evolved in close collaboration with the clients, and the idea of an oak frame building was quickly identified as a high priority. In order to meet the environmental aspirations of the brief, the decision was taken to fully internalise the frame, giving the oak frame a visual presence in every room of the house, and allowing a highly insulated building envelope external to the frame.

AWARDS / PUBLICATIONS

 

Architect : A-Zero Architects

Giles Bruce, Anya Thomas, Phillip Toyin

Quantity Surveyor : Andrew Morton Associates

Structural Design: David Smith Associates

Contractor : Phillips Build Ltd.

MEP Design & Installation: Solo Heating

Photographs © James Whittaker

 
A-Zero Architects_Timber_House_AXO.jpg
 
 

01

Strategy

Embed Passive Performance

This house is designed to have a minimal demand for active heating. High levels of insulation were provided throughout the building envelope, with triple glazing specified throughout. Air infiltration was minimised, with fresh air provided through a MVHR (Mechanical Ventilation Heat Recovery) system. The overall heating demand is estimated at 18kWh/m2/annum, which, through above the threshold for 'passivehouse' is substantially better than a typical new build UK dwelling averaging 50kWh/m2/annum (*)

The residual heat that is required for space heating and domestic hotwater is provided through a ground source heat pump, drawing heat from 1.5m below the ground in the field in front of the building. 

(*) UK Passivhaus and the energy performance gap, Rachel Mitchell, Sukumar Natarajan, Energy & Buildings, 2020

Timber Frame House_Bedfordshire_B_A-Zero Architects.jpg

Strategy

02

Both our clients and ourselves were excited by the idea of using a timber frame as both the primary structure and the main internal aesthetic feature of the project. The timber frame is made of British grown green heart oak, and was installed over the course of three days.

The oak frame is fully internalised within the building envelope allowing shrinkage of the frame without compromising the integrity of the air tightness of the envelope. A steel frame would not have had this problem but the carbon benefit was clear - new steel embodies approximately 12,090 kg CO2e/m3 whereas oak has sequesters carbon throughout the growth of the tree from which it was harvested.

 

Use timber instead of steel

Strategy

Reuse materials that were already on site

Timber Frame House_Bedfordshire_3_A-Zero Architects.jpg

05

The original steel structure was dismantled, although the demolition contractor could not be persuaded to unbolt individual sections, meaning there was some avoidable wastage. The majority salvaged, taken off site for shot blasting, and integrated into the new façade along with new steels. New walls were built of the old bricks, and we used a Flemish bond so that all the half bricks did not have to be thrown away.

 

The original cow-shed was made of four materials – a steel portal frame brick walls, a concrete slab, and an aebestos roof. We sought new uses for these materials to incorporate then back into the new house. This approach significantly reduced the amount of waste that was taken off site, and also made economic sense in terms of reducing the build cost.

We could not reuse the roof as it was asbestos, but we were able to use almost everything else. Instead of pouring strip foundations and a concrete slab, we left the original slab where it was supporting the new timber frame structure on localised concrete pads.

Similar projects