Joymount in Carrickfergus, Northern Ireland, is a 40-home social and affordable housing development under construction for Clanmil Housing Association. Raymond Millar, construction director at the project’s offsite contractor, The McAvoy Group, explains how the company is using modern methods of construction to reduce the build programme by around 60 per cent.
Located adjacent to a Northern Ireland conservation area, the Joymount development for Clanmill Housing Association is set to provide 40 new affordable and social homes for rent to the area using a new offsite housing solution.
When completed, Joymount will provide eight one- and two-bedroom apartments for couples and families, 17 two-bedroom apartments for older people, three detached bungalows, and 12-two bedroom houses for families. Each element in this mix of tenures has been specifically designed to fit its intended resident type, and to be future- proofed to meet changing needs.
Designed by Knox Clayton Architects and constructed by The McAvoy Group, the new homes are being manufactured and fitted out at the Group’s production centre in Lisburn, which is on the other side of Belfast from Carrickfergus, to the south west.
The project is said by McAvoy to be the first offsite affordable housing scheme constructed in Northern Ireland, and according to the firm, the company’s housing solution will reduce the build programme by around 60 per cent to 40 weeks.
The £4.7m contract is being delivered as a single phase, following the manufacture of the apartments and houses at the Group’s Lisburn Factory, with the apartment modules arriving onsite first.
The McAvoy Group, based in Dungannon, Northern Ireland, has been providing offsite solutions and interim modular buildings for nearly 50 years now, and as such was well- placed to undertake the project – though Joymount is the company’s first offsite residential scheme.
According to Raymond Millar, construction director at the Group, Clanmil Housing Association reached out to the company in order to “explore how offsite construction could be used to deliver new housing more efficiently, and in less time.”
“McAvoy had designed a prototype house at its factory in Lisburn, which was very similar to the standard house types that are developed by Clanmil, so there was a good fit.”
Millar believes that the driver for the project was to cut the waiting list for afford- able housing – sharing the rest of the UK’s housing challenges, statistics have shown that Northern Ireland currently has around 24,000 households in a state of ‘housing stress.’ The two organisations agreed that modern methods of construction could help tackle this crisis by speeding up the housing associations’s development pipeline.
Once the partnership began, the next stage was for the housing association to look at potential sites to trial the approach. The Joymount site was identified as being the one most suited to offsite delivery of the Clanmil HA’s project, because of the similarity between the association’s typical homes and McAvoy’s prototype. In addition, the Group was confident that the apartment blocks that would form part of the Joymount development could be ‘modularised.’
When they were first approached, Millar told Housebuilder & Developer that the local community had been “very receptive” to the project, recognising the need for more affordable housing. He said that there “has been very positive feedback to date, and the community has engaged well,” which he believes is in part due to McAvoy’s commitment to work under the Considerate Constructors scheme, as part of the company’s policy to “promote best practice in its site activities.”
A brownfield site, the location previously accommodated a factory unit and a former supermarket, both of which had been demolished prior to the Group taking possession. Beyond the removal of these buildings, McAvoy was responsible for site preservation and enabling works, which included the remaining clearance of the site before construction could begin. The extensive remediation involved removing contaminated ground, sub-structure investigations and levelling the site ready for foundations.
The site already had planning for a mixed affordable housing scheme to be built using traditional in situ construction. The Group was then able to develop an offsite solution for the whole scheme that fit into the existing planning consent.
Millar reports that this was challenging, as it involved later engagement in the process than was ideal.
“Typically, early engagement at the initial design stage is crucial to optimise efficiency for offsite manufacture,” he explained. “Overcoming this challenge on Joymount demonstrates the flexibility of McAvoy and its offsite housing solutions.”
Millar reported that the historic nature of the site raised further challenges:
“The Joymount site is subject to a number of planning conditions relating to the history of the site. It contains some of the remains of Joymount Orchard Wall, belonging to Joymount House, part of which is scheduled for protection under the Historic Monuments and Archaeological Objectives Order (Northern Ireland) 1995. McAvoy is undertaking works to preserve this historic wall.”
“The development site is also located within an Area of Archaeological Potential identified for the historic settlement of Carrickfergus and is close to the 12th Century Carrickfergus Castle. Assurances were required to ensure that any archaeological remains within the site were identified and protected or recorded in advance of the construction works.”
Layout and design
There are two entrances into the site. One for the apartments, which are constructed as four blocks – one three-storey and three two-storey – to the east of the site, and one on the West side by the row of terraced houses on the south side.
Along the north edge of the site are the three detached bungalows designed “specifically for individual families with complex needs.” These bungalows (up to 115.7m2) will provide three or four bedrooms and are designed “for individual families with complex needs.”
Millar told that McAvoy has worked with the occupational therapists for each family to design the layout of the homes to meet their specific requirements. “Features include wheelchair-accessible kitchens with adjustable worktops, occupational therapy stores in each home for the storage of equipment, sensory rooms, and carer bedrooms,” he detailed.
Overall, McAvoy has manufactured 111 steel-framed building modules for the scheme in its offsite factory, and the homes are currently being installed onsite, complete with bathrooms, kitchens, partitions and glazing.
Each of the new homes across the site have been designed in accordance with the Lifetime Homes and Secured by Design standards. This means the homes have been specified more secure locking mechanisms and handles for the windows and doors, non-removable glass to the windows and patio doors, wider doorsteps to accommodate wheelchair access, and adjustments to beams in the terraced homes to provide the facility for a hoist to be installed and platform through-floor chair lift if required in the future.
The design of all of the homes is intended to reflect its location, and as such draws inspiration from the historic buildings nearby. Materials such as slate roofing, white render and timber windows have been selected with this in mind, and are in keeping with the Conservation Area.
As to the homes’ ecological properties, each residence will benefit from timber- framed double glazing. The homes are also required to achieve a ‘B’ energy and, according to Millar, “more precise factory construction processes, less material waste and high levels of insulation help reduce heating costs and energy consumption.”
The offsite process
After being manufactured at the Group’s offsite production centre, the residences are being transported by road as steel-framed modules to the site, where they are then craned into position.
The terraced homes (73.4m2) are constructed using four modules, the 2-bed apartments (64.8m2) have two modules, the 1-bed apartments (up to 60m2) comprise three modules to suit their orientation in the building design, and the bungalows have up to six modules.
The detached bungalows have a steel- framed post and beam point loaded system with a timber floor. The apartments are constructed from the same system, but with concrete floors to provide additional acoustic performance above and below each apartment. The terraced houses use a light gauge steel-framed system with a composite floor.
The central cores for the apartments, which accommodate the stair towers, lift shafts and circulation areas, are also manufactured offsite.
As there are two different offsite housing systems on this scheme, two types of foundations were used. These were traditional poured concrete strip foundations for the terraced houses, and pad foundations for the apartments and bungalows to accommodate the point-loaded steel- framed system.
On the buildings’ exteriors, the facades are rendered and the roofs have cement- fibre slate tiles, which were a requirement of planning. As for the roofs, they will be tiled on site. “This work could have been carried out in the factory, but the orientation of the modules and roof layouts would have needed to change,” explained Millar. “As the project already had planning consent, the client was keen to avoid any delay to starting construction of the new homes, so the decision was taken to tile the roofs on site.”
The construction director listed the “pace of the residential supply chain” as one challenge that this modern process introduces, one that that is reportedly faced by many offsite housing manufacturers.
“Lead times are often much longer than those required for offsite manufacture for other sectors such as healthcare and education,” Millar explains. He argued however that “the growing demand from the offsite sector for greater speed and shorter lead times from suppliers of domestic products will address this as the offsite housing sector becomes more mature.”
Success so far
The construction director holds the company’s offsite methods as accountable for the development’s success so far, and argues that the method holds many benefits: “The greater certainty and predictability of offsite manufacture is helping to address the rising cost of build- ing materials, the shortage of skilled labour in the construction industry in Northern Ireland, and the uncertainty created by Brexit.
“Offsite manufacture has avoided delays caused by poor weather, particularly during the winter months, and it improves both quality and health and safety – with less impact on the environment.”
He stated that the project has been a “tremendous springboard” for the Group’s expansion into onsite housing. “It successfully demonstrates how offsite can be used for a number of different housing types in a single scheme – detached, semi-detached, terraced and apartments. It will also demonstrate how offsite can help reduce programme times.”
Millar concludes: “It is fantastic to see such a progressive provider of social and affordable housing as Clanmil, who are looking at more innovative ways of providing high quality new homes more quickly to address the housing shortage.”