Crofts Street

Crofts Street, Cardiff, is a modular housing project comprising nine two-bedroom council houses, designed to be carbon positive in operation and built on brownfield land. It is the city’s first modular scheme delivered by Cardiff Living, which is part of Cardiff Council, as part of the Council’s flagship housing programme to offer around 1,000 homes across the city to tackle the growing demand for housing.

The co-production between @HOME, Aecom, Wates and RSHP uses a ‘fabric first’ approach to optimize the performance of each unit against weather conditions, fire, and acoustics. This system reduces operational energy consumption, which can lead to major cost savings on utility bills for residents and reduce maintenance needs during the building’s lifetime and was awarded Welsh Government Innovative Housing Funding. Each home has been designed using a hybrid of sustainable materials enabling them to exceed Passivhaus standards and current regulations in fire, acoustics, and thermal installation.

Ninety-five percent of each module is assembled and finished off-site with quality-assured factory production. The use of sustainable materials is prioritized, which means that the homes 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 are fossil fuel free, all supported by electric use only with on-site renewable energy generated by roof-mounted solar panels and battery pack (predicted to generate 58 kWh/m2/yr), far-infrared electric heaters and a wastewater heat recovery system. The simple addition of the solar panels is sufficient to generate more energy than is required to run the regulated building services (e.g. heating, hot water, lighting, pumps and fans). Mechanical ventilated heat recovery and natural ventilation provide efficient year-round comfort, and annual heating bills will be 90% less than for a traditional build. The modules have an EPC Energy Performance Certificate of A111 with in-use operational energy data showing 9.22 kWh/m2/yr (energy consumed from the national grid), well below the RIBA 2030 Challenge domestic target of 35kwhr/m2/yr.

The houses also have a low upfront embodied carbon design of 313 kgCO2e/m2 (A1-A5) almost achieving LETI target A, the designated target for projects built beyond 2030. The embodied calculations were done by RSHP post-practical completion to measure the environmental impact of the project. The two-storey, terraced council homes sit on an unused inner-city brownfield site parallel to the existing neighbouring properties, reflecting and continuing the brick materiality of the existing architectural language.

Quick and cost-effective volumetric technology and off-site assembly allowed the homes to be delivered on-site within two weeks, minimising local disruption, reducing site traffic, emissions, and waste, and accelerating the occupation of the 100% social housing scheme.

The Crofts Street project in Cardiff is setting a new benchmark for council housing in the UK - and positively changes our concepts about house building in the future.