RSHP designs new net zero carbon modular council homes in Wales

CGI of volumetric housing at Crofts Street, Cardiff (RSHP)

Forum member Rogers Stirk Harbour and Partners (RSHP) has been talking about its first net zero carbon modular townhouses that have now arrived on site at Cardiff's Crofts Street, as part of Cardiff Living, Cardiff Council's flagship housing programme with Wates Residential.

The houses designed by RSHP are a joint project with AECOM which has provided the engineering and delivered by @Home. The 100% affordable two-bedroom family homes have been built on a highly constrained brownfield site and the INNO design uses a 'fabric first' approach to optimise the performance of each unit against weather conditions, fire and acoustics. This in turn reduces operational energy consumption, which will lead to major cost savings on utility bills for residents.

The townhouses prioritise the use of sustainable materials, which means that they have less embodied energy than other buildings. With these considerations, the scheme is expected to surpass the current (Part L1A 2013) Building Regulations standards by 142% for regulated carbon emissions and 42% in fabric energy efficiency. The homes use roof mounted solar panels and heat pumps, instead of gas, to provide energy.

Mechanical ventilated heat recovery and natural ventilation are used to provide efficient year-round comfort to all internal spaces. As a result, the Predicted Energy Assessment (PEA) for Crofts Street indicates a negative emission of at least -1.66 tonnes of CO2 per annum per home.

Ninety-five percent of each module is manufactured off-site, within a quality-controlled factory setting. Once they are ready, four modules that compose two homes are delivered to site each day. The speed of delivery and construction allows the Council to make homes available to tenants on its existing housing waiting list in just five weeks.

Ivan Harbour, Senior Design Partner, at RSHP said:

'I am proud to be working on council homes for the first time. Crofts Street demonstrates that together it is possible to deliver exceptional quality, affordable and carbon positive housing, which is very quick to build, with little disturbance to neighbours. Collectively, we hope to change the way we think about house building in the future.'