The property is an old Victorian brick barn that was formerly used for storing cattle feed. The planning to convert this barn into a house was gained on the basis of the job being an ecological conversion, particularly as it is in an Area of Outstanding Natural Beauty. The client was keen to see an energy-efficient building designed to be delivered under commercially viable budgetary constraints, so Ecotecture highlighted the Passivhaus standard as the most cost-effective means of reducing their reliance on fossil fuels.
Balancing the realities of achieving a Passivhaus-certified building against increased construction costs, particularly relating to the conversion of existing structures, we found a compromise in the form of the AECB Silver Standard. Whilst this building hasn’t been certified to meet the standard, we felt confident that the end result is certainly a good way towards it.
Initial calculations showed the barn converted to house achieving an annual heat and cooling demand of 24Kwh/m2 per year, meaning that it would be very efficient. To achieve this level of energy efficiency, we had to address the thermal bridging issues which are inherent in the conversion of this nature.
The calculated u-values from PHPP achieved 0.14/Wm2K on the walls on the roof and 0.1/Wm2K on the floor construction. Psi values were not calculated for inclusion within the PHPP as it was not considered financially viable, good practice was included when developing the construction details for low thermal bridging, and PHPP was developed using the typical thermal bridging allowance.
For this project we have completed the RIBA Stages 1-4.
Stage 1 - Preparation & Brief
Stage 2 - Concept Design
Stage 3 - Spatial Coordination
Stage 4 - Technical Design