Sustainability Report

Sustainability information provided by Rob Elkins, Creative Director at Artel31 and House in a Barn project lead.

Embodied carbon overview

• House in a Barn records upfront carbon of 245 kgCO2e/m² and life-cycle embodied carbon of 330 kgCO2e/m². The project’s embodied carbon calculation records A1–A3 material production emissions at approximately 180 kgCO2e/m².
• The project includes polycarbonate walls supplied by Varico and designed by Artel31. The timber frame was supplied by Allwood Timber Frame and manufactured off site as a panellised system.
• Reuse and repurposing were central to the construction process. All waste produced from removing components from the barn was either reused in the build or stored in the adjoining farmyard for future use. The original precast concrete panels and steel frame are left exposed, retaining existing material on site and maintaining a visible connection to the barn’s agricultural past.
• Reclaimed concrete silage panels were incorporated in a non-structural role, acting as spatial dividers and visual reminders of the building’s former use. Exposed concrete flooring and reused concrete walls also contribute thermal mass within the scheme.
• The external privacy screening uses railway sleepers reclaimed from a demolished barn, which had itself been built using sleepers from the railway when it was refurbished years earlier. Old staddle stones, formerly the bases of a granary, were reused to support a timber pergola.
• Beyond the main reuse strategy, particular design and construction decisions helped reduce material use and waste. The project followed the old idiom of ‘how would a farmer do it’, with apparently non-conformist column positions used to reduce beam sizes while maintaining significant clear spans. This also supports future adaptability, allowing internal walls to be moved if the house is sold to a different family.

Operational emissions overview

• The project is all-electric, with no gas used on site. Reported actual energy use is 37 kWh/m²/yr, supported by 5,000 kWh/yr of renewable generation. The project achieved a SAP A rating of 95 and an Environmental A rating of 100.
• The building was designed to minimise energy use through high levels of insulation, airtight and vapour-open timber-framed construction, passive solar gain, and efficient building services. U-values were recorded at 0.145 W/m²K or below across the thermal envelope.
• Building services include mechanical ventilation with heat recovery, photovoltaic panels, and an air-source heat pump. Large thermal stores were installed to balance the heating and cooling cycle, which can be significant in an exceptionally insulated timber-frame build.
• The project references the use of Passivhaus software, natural light modelling, and wind studies. These tools informed design decisions around window sizing, orientation, comfort, energy performance, and climate resilience.
• Early spatial planning came from both directions: outside-in, by removing portions of the existing barn, and inside-out, by adding new component parts and climatic zones to ensure high-quality internal light, air, and temperature. This made the process considerably convoluted, with conflicting information from the two methods. The use of the various software tools allowed Artel31 to rapidly evaluate and contrast different solutions.
• Passive control of solar gain and intermediate spaces allows the clients to move around the barn and its semi-enclosed external shell as the climate and weather supports. The existing barn also acts as a protective outer layer, with some spaces positioned outside the thermal envelope to provide varying degrees of shelter and exposure.
• Reported potable water use is 170 litres per person per day. Artel31 notes that water usage has been relatively high, primarily due to a dry summer when new planting needed to be regularly irrigated. It is hoped that long-term water usage will drop to below 90 litres per person per day.