Jack Wooler explores the architects’ strategy behind a social housing scheme in Much Wenlock, Shropshire – a project which shows how Passivhaus can be achieved in a design that also worked with difficult terrain
On the steeply sloping site of Callaughtons Ash, Much Wenlock, a new social community is now up and running, providing an exemplar in sustainable building. Completed in July 2018, the £2m development of one, two and three bedroom homes displays locally sourced clay tiles and bricks with UK grown timber cladding, all built to the Passivhaus standard. The stringent albeit voluntary test far exceeds Building Regulations and requires a mixture of reduced heat loss from a highly insulated structure, plus passive heat gains, to vastly reduce overall energy consumption.
Comprising two shared ownership and 10 homes for social rent, the super-green development is intended as a model for sustainability, unlocking small greenfield sites, and improving the quality of family living in rural areas of the West Midlands. Architype, a practice based in neighbouring Herefordshire which specialises in ecological design, was responsible for this project. As such it has been heavily involved in the process from start to finish. They were not chosen by chance; the architect’s managing director (Jonathan Hines) had previously given the client a talk on sustainable design and Passivhaus, and identified this housing project as an ideal pilot for testing out the standard in the area.
The finished development has achieved this ecological ideal successfully, with social housing proving to be an ideal place for the standard to flourish – leaving residents better off both in terms of their finances and their wellbeing, and providing another exemplar case study of hitting the standard to add to the practice’s portfolio.
As part of the neighbourhood development plan Much Wenlock town council have been undertaking, a specific set of objectives was decided at the outset.“Some of that involved high quality design space, utilising local materials, aspirations for high levels of sustainability, and quite involved consultation,” says Paul Neep, associate at Architype. “Also, what was key of course was the delivery of social housing, because it is an area of Shropshire where people are having to move out because of the cost of living within the town.” This neighbourhood plan, alongside the lack of affordable housing in the area, were the initial drivers of the scheme – with the Shropshire Housing Group, who have now become part of the Connexus Group, working in close collaboration with the town council to achieve it. The architects worked alongside the client closely during this time, “almost as a combined process,” says Neep. “All the consultation events, and a lot of the design workshops included representatives from the council, as well as from the client group, in order to develop what they could see as being an aspirational project – an example of how development should be undertaken in Much Wenlock.”
Being involved in the process early on, the architects were able to work with the project team closely right from the planning stages, benefitting the scheme greatly. Planning is rarely the simplest part of the development process however, and this can be especially true of greenfield sites. “It helped that the neighbourhood plan was developed to a certain level where it was going to support development outside the settlement boundary, based on the fact that it would be social housing,” explains Paul Neep. “So actually having the plan developed to the extent it was, and having the support of the town council throughout, carried some weight, and gave us a much smoother ride than it would have been otherwise.” The architect adds however that the project team still had to explicitly justify the reasons why the development was appropriate on that site, and how the design of the scheme was appropriate for the location. This was again achieved largely by the project’s adherence to the neighbourhood development plan and its aspirations. For example, the practice specified local materials and styles, taking reference from architectural precepts within the town, while delivering high levels of sustainability, and providing the project with a sense of community and place. In addressing the concerns, adds Neep, “we actually had the opportunity to do something the planners were quite keen on seeing come forward anyway.”
Finding a site was of course an important part of the early process. The team were blessed in this respect – when the practice first got involved, the architect had the opportunity to review five sites across town. As part of the neighbourhood development process, there had been a call for sites, and various land owners had put their sites forwards. “We took a trip around the town and reviewed them all,” says Paul Neep, “alongside consultants looking at access and highways, and drainage as well, and did a bit of a process of reviewing the broad constraints, opportunities, and capacities of the sites.” The one that was eventually chosen was the one that presented the least constraints, particularly with regards to drainage, but it is actually quite a steeply sloping site. There is around a one in 10 gradient across most of the site, which of course introduced challenges into the design and build processes – including the knock on effect of the gradient on water run off from the nearby fields. Neep explains the challenges this proposed: “A farmer’s field extends quite a long way further up the hill, so in extreme storm events the road at the bottom of the site was typically in quite deep water – so trying to manage that through the design process was quite challenging.” Another issue thrown up in addition to the close proximity to the nearby agricultural land was the adjoining residents. The site is on the very edge of the development boundary, and as such the nearby residents were an important part of the consultation process: “I can’t say they were completely happy,” says Neep, “but I don’t think people tend to be when there’s a development going on in the field next to their houses.” “But still, most of them were brought round by the end of it – after what we went through with them in terms of consulting, having explained the project’s ethos and quality of the design.”
Such a sloping site proposed challenges to the layout of the development, with the terrain having “more effect on the design of the layout than anything else,” says the project architect. The team reportedly went through an “amazing” number of iterations of possible layouts for the project; as Neep explains – “when you have a steeply sloping or otherwise difficult site, small changes can ultimately result in even the best layout needing a complete redesign.” The layout that the team arrived at was focused around the homes being as close to south facing as possible, in order to maximise the solar gain necessary for Passivhaus living. “In terms of the orientation,” adds the architect, “with Passivhaus, it’s about creating a good balance between window sizes in order to make sure you get enough solar gain, and minimising the heating risks during hot weather – that itself had quite a big impact on the design of the houses and how they look.” These nearly-south facing homes now gently follow the contours of the land, making the site work as well as possible in terms of access to the dwellings – with an entrance into the site leading to a public space in the middle of the homes. This access to the homes wasn’t just important in terms of the project’s functionality, the space was also utilised in creating a sense of community: “The idea was that it is a cluster of houses arranged around a central public green space, that all the houses look back onto and have an interaction with, with parking arranged off it and the road going around them.”
The sloping site appears to have been a factor that runs through almost all aspects of the project, including the buildings’ materiality: “The terrain gave us an opportunity to utilise some of the high quality materials we had specified into the landscape, with elements of brickwork integrated around the buildings and in the plinths of the homes, giving a little more interest into the level design.” The ultimate client, the Shropshire Housing Group, were continually consulted in the specification of such materials – and what they wanted was for the project to have a feel of the locality. “In terms of the materials palette across the site, it is very typical of Much Wenlock,” explains Neep. This is especially exemplified in the clay bricks and clay roof tiles that can be seen across the development. All the way round the plinth of the houses are clay bricks, which have also been used within the retaining wall structures. “The clay roof tiles themselves were actually quarried and made within 25 miles of the site – in Brieley Hill,” says the architect. “The lime render was from a company in Much Wedlock itself as well, and so we were able to support the local economy in that way.” The timber cladding is something that went back and forth between the practice and client for some time: “They were incredibly keen on finding a timber cladding product which had a more defined lifespan on it, and we typically as a practice use more natural, ‘hairier’ type timber cladding products, such as douglas fir, larch or cedar.”
What the practice eventually found was a thermally modified timber cladding. Uncommon in this particular context, it’s a UK-grown hardwood – poplar. While not typically used in construction, the thermal modification process makes it more durable, and as such, suitable for this type of use. “Ultimately,” says Neep, “what we were able to do was deliver a timber cladding which was much crisper in its detailing, more robust, and less susceptible to movements and mould growth.” That addressed a lot of the concerns that the client had, as well as a lot of the concerns that were raised during the consultation period. “There are some examples nearby where timber cladding has been done badly – so this was an opportunity to provide a more robust, stable, and attractive product, as well as being UK grown,” he adds. The interiors of the buildings were left largely down to the Shropshire Housing Group and their standard specifications. With many of their maintenance items already being in stock, there was little want for any major differentiation from their typical interiors. It was important however that the buildings be easily maintainable, so the architects went through “quite an involved” process with their maintenance and repair teams to look at how to make that as straightforward as possible for them. The architect adds: “I think the internal environments created by Passivhaus, with the fresh air, daylight from windows, and the good levels of ventilation, in themselves made it an incredibly comfortable place for residents, regardless of specification.”
Reflections & reactions
The project has gone down well so far – especially with the town council and the neighbourhood planning department. “I’ve spoken to the local councillor and other members of the council, and they’re all incredibly keen for further phases to take place,” says the architect. “It’s looking absolutely stunning; everything is weathering, the timber’s looking great now, and the landscape has just made everything settle in.” At an event the project team hosted recently to unveil the Passivhaus plaque, the architects were also able to meet some of the scheme’s residents. “I had a chat with some of them, and the stories we are hearing back about how little heating that’s been required has been absolutely fantastic,” says Neep. “I heard one of the residents say that they only switched their heating on for a couple of days last year, and even then only for the early mornings to heat up the bathroom on the building’s north side.” Besides the anecdotal evidence, the team are just about to get the first year’s worth of monitoring data and post-occupancy studies, which will be analysed to find out just how everything is doing – though it seems clear from the residents that everything is performing as it should. Neep concluded: “It’s been a great project to be involved with. We’re already working with a few other local authorities and social housing providers across the country, so there certainly seems to be a lot of interest in the project – we hope we can be involved in a few more.”