This access directed the basic construction strategy more than any other issue. Buildings of this type can be built using a range of off-site construction systems, such as SIPS timber panel systems or prefab modules, but these all require crane access, which was not a practical option, so in collaboration with the engineer the building was designed around a lightweight steel frame, made out of a large number of small pieces that could be carried into the site by hand. This system had the added benefit of being very light, which was less likely to unsettle the many surrounding old buildings.
The first step was to clear the existing buildings on site- three derelict workshops that had been home to a troupe of pigeons for several years.
We then underpinned the surrounding buildings- the site is bordered by a 4m high wall on all sides, and this Victorian wall had practically no foundations on three sides. The overall height of the building was very restricted by planning issues, so we needed to lower the ground floor by 450mm. Even this modest change in level involved exposing the brick corbels to the surrounding wall, so a full underpin was needed to three quarters of the boundary- quite an awesome task, particularly as all digging was by hand to avoid disturbing surrounding buildings.
Next a raft foundation was poured over the site. This foundation has no footings- it spreads the loads evenly over the entire site, and allows columns to be fitted wherever they are required.
The lightweight steel frame was then installed- this was the largest subcontract on the project which made for some complex co-ordination between designers and contractors. There was quite a long delay to the delivery, as the supplier was supposed to make a detailed survey of the site and fine- tune the steel design accordingly. When I got the first steel drawings for review I was more than slightly suspicious to see that the setting out was identical to our drawings, made from a pre-demolition survey of the site! The question was whether to force responsibility to the contractor and risk a problem, or take the huge risk of surveying ourselves- I took a deep breath and measured up the site with a disto laser- quite accurate, but not really up to this task, particularly as non of the site walls were straight.
We drew and re-drew the setting out, trying to allow for all the curves and distortions of the side walls, then ordered the steel. When it turned up on site it miraculously fitted, although it was very lucky we had designed two separate frames- these had to be angled slightly to one another to make the frames fit the site.
All things considered the steel frame came together quite easily. There was some colourful commentary on the design when it came to bringing the beams to the main ground floor span on site- these were not light weight at all, to the extent that the tyres on a little trolley the installers used exploded. Somehow the steel was manhandled into position and winched up into place, and once the cross bracing went in we had a stable structure.
From this point on the building technologies were more traditional, and more along the lines that the main contractor was used to. The entire site was lined with a basement tanking system, as many of the surrounding walls were exposed to the elements with dubious waterproofing credentials, and then the steel frame was lined with timber stud.
It’s an interesting paradox that so much timber was required to make this steel structure into a building, to the extent that I would describe the end product as a timber framed house stiffened with a steel frame. We had intended to use industrial metal stud, but the contractor felt that this would give a ‘hollow’ feel to the finished building and recommended a stiffer timber stud. Watching the spaces of the building slowly emerge as skilled Polish joiners formed every surface from timber was the most exciting phase of the project. When the first floor joists were complete, I found out to my surprise that there was a fantastic view of surrounding urban gardens from the bedrooms!
The parts of the building facing the noise and smells of Chapel Market’s restaurants and shops to the North are faced in concrete blockwork, but to the South the timber frame is exposed. Breathable membranes were wrapped around this frame, clad in coppice-cut sweet chestnut from Kent, a sustainable material cut from young trees that needs no sealant or maintenance.
The roof was finished with a cold applied liquid membrane. This is applied like a paint over a fibre mesh, giving a homogenous surface without any of the weak joints of a standard bitumen system, or the dangers of a hot melt asphalt on a timber building.
All of the exterior joinery was hand made by the contractor himself from solid Walnut. I was very lucky to have a contractor with the skills to produce this kind of work- it cut down all the co-ordination that would have been needed if the joinery was sub-contracted, and allowed the details to be designed and negotiated as the build progressed (not an advisable design strategy given the contractual risks, but it gave us a great opportunity to develop the design as the build evolved)
The contractor went on to hand build all the internal joinery, including internal doors, the kitchen from scratch, bathroom vanity units and wardrobes, to the extent that every piece of fitted furniture was created bespoke for the building.
When the buildings were finished Katherine and I decided that the opportunity to live in a home that I had designed was too great to miss, and we moved in to one of the houses. The design of the houses as first complete was purposely plain internally, to allow the inhabitants to personalise the their space. Once we had moved in, however, we decided to build in some extra joinery to make it our home.
A long two person desk now completes a study in the spare bedroom (with an extra wardrobe for long dresses- the architect rapped on the knuckles for previously overlooking the need!). The small ancillary room to the main living space has been made into a snug, with a fitted sofa, and a collage of shelving, orange lights and recesses for sculpture and objects.
Finally, a new door to the alleyway and a post rack has concluded my first new self build, and at four years since the search for a site began, it’s a welcome relief to finish! Now I’ve finally got time to look for another site….
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