An embodied carbon analysis undertaken by Eilidh Forster of Woodknowledge Wales to a measurement methodology agreed by RIBA and RICS returned a value of 253 kgCO2/m2 which is a 16% improvement on the RIBA 2030 target. See below (graph)
This project really does represent an effective response to the climate emergency and demonstrates that Welsh Government should implement an embodied carbon policy so that all homes in Wales are required to be low carbon. This is one of the policy recommendations in our Zero Carbon Homes report launched at WoodBUIILD 2019.
The 36-unit housing Innovative Housing Programme supported scheme in Llanbedr near Ruthin is one of the exemplars for the Home-Grown Homes Project and provides compelling evidence for timber construction using Welsh trees. Welsh grown spruce supplied by Pontrilas Sawmills was used for the structural frame and larch grown and processed near the site was used for the external cladding. All joinery elements were wood based, and wood fibre insulation was used as an alternative to petrochemical foams.
Now that the Llanbedr project has beaten the RIBA 2030 target for embodied carbon, the Home-Grown Homes team are turning their attention to measuring the operational carbon emissions – the emissions associated with the buildings use. The design energy performance suggests a level that approximates to the RIBA target for 2025 – 70kWh/m2/y. See below (chart).
RIBA 2030 Climate Challenge target metrics for domestic buildings
However, RIBA demands that the operational energy performance is determined through post occupancy evaluation rather than using design energy performance. Over the next 6 months, Cardiff Metropolitan University with the support of Build Test UK aim to conduct an energy performance evaluation using established and novel techniques. This evaluation will determine if the building can be expected to perform at or near its design energy performance to provide a truly low carbon and sustainable home both in construction and use.