A development of offsite-manufactured homes in Bristol aims to demonstrate how small urban brownfield sites, such as garage plots, can become a catalyst for creating low-cost sustainable housing<\/p>\n
The scheme of nine one-bedroom, two-storey homes was built on a council-owned disused garage yard in Bristol\u2019s northern suburb of Horfield. Credit: BDP<\/p>\n
With the government\u2019s ability to deliver a targeted 1.5 million new homes in England by 2029 in question, and the impact of a swathe of new planning reforms still to be felt, the pressure is on to find speedier ways to unlock sites for development.<\/p>\n
A resurgence in smaller-scale infill residential projects, for example on former garage or high-street gap sites in towns and cities, may be a key part of the solution. Pro-development campaign group the YIMBY Alliance<\/a> has estimated that this type of opportunity could provide up to 30,000 new homes a year.<\/p>\n Design practice BDP<\/a> devised its Gap House<\/a> concept to help Bristol City Council<\/a> meet an acute housing need by squeezing low-cost, factory-constructed eco-homes into small urban spaces, including garage plots.<\/p>\n The first scheme of nine\u00a0one-bedroom, two-storey Gap homes has now been built on a council-owned disused garage yard in Bristol\u2019s northern suburb of Horfield, close to Southmead Hospital.<\/p>\n \u2018Huge opportunity\u2019 in reusing garage plots\u00a0for housing<\/strong><\/p>\n Commissioned by the local authority\u2019s housing development team and funded by its housing and landlord service, the properties were constructed, by main contractor\u00a0Beard Construction<\/a>\u00a0and\u00a0modern methods of construction (MMC) specialist Etopia<\/a>, using high-performance offsite manufactured structural insulated panels (SIPs) for an estimated cost of \u00a32,000 per m2, equivalent to around \u00a396,000 for each home, according to BDP.<\/p>\n Each home has a 40m2\u00a0(8m x 5m) footprint and features an open-plan kitchen\/living area and bathroom on the ground floor, and a bedroom and storage on the first floor, with a balcony area sandwiched between adjacent properties. A compact street-facing green space and outdoor seating was conceived to encourage social interaction and community connection.<\/p>\n High levels of insulation enabled by the use of MMC, in combination with low-energy lighting, renewable energy generated by solar PV panels and an air-source heat pump, should result in a predicted 40.5kWh\/m\u00b2\/yr energy use, compared with the average annual modelled energy use for homes in England in 2022 which was 231kWh\/m\u00b2\/yr.<\/p>\n Matthew Mayes, project director at BDP, tells RIBAJ: \u201cOld garage plots represent a huge opportunity in Bristol. This type of site lends itself to repetition and replication, bringing\u00a0economies of scale, which is really needed to make it work from a financial point of view.\u201d<\/p>\n Exploiting advanced construction methods<\/strong><\/p>\n Gap House was first unveiled by BDP at the Bristol Housing Festival in 2018 and the concept was developed further through an Innovate UK-funded demonstrator programme, initiated by Bristol City Council and a consortium of partners in 2020, to benchmark MMC home building against existing delivery models.<\/p>\n The council was keen to exploit advanced construction methods to address a shortage of social-rent\u00a0homes by developing small brownfield sites in public ownership, located in existing communities and close to amenities.<\/p>\n Bristol had an estimated 2,000 garages on 300 different council housing estates suitable for redevelopment in 2018, and according to BDP\u2019s own estimates there are 15 brownfield sites suitable to deliver 10 units each within 30 minutes\u2019 walking radius of Southmead Hospital alone.<\/p>\n The homes in Horfield are a contemporary take on a terraced street, their compact form and monopitched PV-lined roofs reminiscent of Stirling Prize 2024-shortlisted Chowdhury Walk<\/a> in Hackney, designed by Al-Jawad Pike \u2013 another project by a council trying to develop small, underused sites.<\/p>\n The SIPs forming the superstructure for the homes measure up to 6m wide by 2.4m tall. A separate glulam ring frame supports intermediate floor joists with further SIPs panels forming walls for the first floor, capped by the timber roof trusses. The windows, zinc cladding and roof joinery were installed through separate packages.<\/p>\n Site access to the garage plots was via a single narrow access road, making Etopia\u2019s 2D flat-packed system preferable to bulkier volumetric modular options that require space for cranes. \u201cOther benefits of the system include less waste, fewer people on site, which is advantageous from a health and safety point of view, and better quality,\u201d says Mayes.<\/p>\nBDP\u2019s Bristol Gap House for garage sites, from inside to out. Credit: BDP<\/p>\n
Each compact home features an open-plan kitchen\/living area and bathroom on the ground floor, a bedroom, storage and an external balcony on the first floor. Credit: BDP<\/p>\n
Predicted energy use is 40.5kWh\/m\u00b2\/year thanks to high levels of insulation, low-energy lighting, renewable energy generated by solar PV panels and an air-source heat pump. Credit: BDP<\/p>\n