RSHP and AECOM’s first net zero carbon modular townhouses arrive on site

02 December 2021

Nine net zero carbon townhouses arrived on site by lorry his week at Cardiff’s Crofts Street, as part of Cardiff Living, Cardiff Council’s flagship housing programme with Wates Residential.

Designed by architects Rogers Stirk Harbour + Partners (RSHP), engineered by AECOM, and delivered by @HOME, the 100% affordable two-bedroom family homes have been built on a highly constrained brownfield site.

The INNO design, led by RSHP and AECOM, 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. This shows that the simple addition of solar panels is sufficient to generate more energy than is required to run the regulated building services (i.e. heating, hot water, lighting, pumps and fans).

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. Once the modules are installed on site, services will be connected, and the landscape and exterior works completed, to allow the Council to make homes available to tenants on its existing housing waiting list in just five weeks.

Peter Flint, Director, AECOM says “It’s fantastic to see the townhouses arrive on site, beginning the rapid installation of our affordable residential solution for Cardiff Council and Wates Residential that will make these high-performance homes available for tenants in just a few short weeks. Their speedy offsite construction minimises waste and site activity, including vastly reduced levels of construction traffic. Our design with RSHP demonstrates how a design for manufacture modular approach can deliver high-quality, durable, and low carbon homes both quickly and efficiently.”

Ivan Harbour, Senior Design Partner, Rogers Stirk Harbour + Partners (RSHP) says “I’m 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.”

Andrew Partridge, Associate Partner, Rogers Stirk Harbour + Partners (RSHP) says “It has been a great opportunity to work with Cardiff Council, with the support of the Welsh Government through their Innovative Housing programme and facilitated by Wates, in setting a new benchmark for Council housing in the UK. This project is particularly special to me as I grew up in the area.”

John Green, Director, @Home says “As a team we are very excited about seeing Crofts Street’s great council houses produced in our Nottinghamshire facility. It only took 7992 operative hours to produce these 9 units or 888 hours per house which is incredible. The benefits of carbon positive homes to the end user are what drives us all forward. We have been very fortunate to work alongside Cardiff Council and Wates Residential.”

INNO, is a joint venture between RSHP and AECOM, with over 15 years of research and development, we have designed, engineered, and delivered volumetric housing schemes for YMCA Mitchem, Lewisham Council and have recently completed Park View, a 39-unit modular residential scheme for YMCA Thames Gateway.