We built this house ourselves, including demolishing an old agricultural out-building that stood on the site. We under-estimated the scale of the task and how long it would take: just short of three years. Looking at it now it is quite hard to believe that we managed to do it.
We designed the building ourselves, but then had a local architect take a look at our sketches to suggest some improvements and also convert the sketches into proper drawings.
Because Shrub Farm is Grade 2 listed, the local heritage officer had to give approval and he was very keen to ensure that our design didn’t use traditional vernacular materials, such as clay pantile roofing or look like a 16th century cottage, but was contemporary and referenced an agricultural outbuilding. Which was fine by us.
Straw is cheap, environmentally friendly, highly insulating and easily available (if you live in Suffolk). Building in straw requires little prior knowledge or skills and there is book called Building with Straw Bales by Barbara Jones of Straw Works which is the equivalent of an Ikea flat-pack set of instructions for how to build a straw bale house. This, plus the detail drawings on the Straw Works web site, give you all the information you need.
Clearing the site – Spring 2015
There was a 1960s multi-purpose breeze block agricultural building on the site. This had to be taken down (by hand) including the careful removal of the individual concrete fibre (and asbestos) roof panels.
Car tyre foundations
We used pillar foundations made from car tyres filled with gravel. This is because these were easy to do and didn’t involve pouring tonnes of concrete. They are also ‘self-draining’ in that moisture can move downwards through them via gravity, but can’t soak back up via capillary action. This is why you must use gravel and not sand or rammed earth. When building a straw house it is critical to ensure that moisture can’t accumulate at any point and can always escape through the walls or down through the foundations.
The box beams
A load-bearing straw house is a bit like a sandwich – with the straw as the filling and the bread being timber ring beams – the bottom beam bridging the pillar foundations with the top one spreading the weight of the roof across all of the walls (no point loads). We made the bottom beam in sections, under cover, and then moved these out onto the car tyres. We then used this as the template to cut the pieces for the top beam, which were then assembled on top of a scaffold frame suspended over the foundation beam.
Rain is your number one enemy and it is therefore a good idea to create a roof before you build the walls – using a scaffold framework to hold it up. Once the scaffold is in place you can assemble your roof ring beam, held in position using screw threaded acrow poles which would then allow the roof to be winched down on top of the straw walls once they are in place.
Raising the roof
Once the roof ring beam was in place we (plus friends and neighbours) spent a morning raising the four roof trusses. We then wrapped these with a series of tarps to create a temporary roof. The reason we couldn’t put the permanent roof in place was that we were going to use solid pre-insulated sheets and it was necessary to drive long hazel stakes down through the roof plate into the straw. Also the weight of the final roof on the scaffold plus risk of distortion when lowering it down and the risk of it blowing away made us nervous.
Walls – Spring 2016
We then put some vertical timbers in place that would hold and position the windows and doors and set about putting in the straw, like lego bricks. This was actually the easiest part of the whole process.
Once the walls were in place the roof frame was slowly winched down onto the straw, hazel poles were driven down through the roof plate to hold it in to the straw and then the walls were compressed, using heavy duty ratchet straps. The walls were then held in compression using high-strength packaging straps wrapped over the roof beam and through the foundation beam. It was then work of a weekend and some willing helpers to put the pressed steel insulated roof panels in place. This was a very simple ‘warm’ roof which required no further finishing: the underside of the panels and supporting timbers remained exposed inside the building.
Render and windows
We then spayed lime render onto the outside. It has to be lime, because it is weatherproof, breathable and flexible. We discovered a magical product called Limecote which is very easy to work with and took all the angst out of what is often seen as a tricky process. Once two coats of lime were on, we fixed the windows in place – and the building was weather tight – just in time for winter.
Inside rooms and walls – Winter 2017
Over winter we turned our attention to the inside, putting in the floors, bathrooms and first fix electrics and plumbing (we got an electrician and a plumber in to do this, because this is definitely where you need an expert). Then it was time to plaster the walls using clay – this took about three months!
The boring stuff like putting the kitchen in, installing the en-suites, laying floor boards, finishing-off the windows, painting etc. This takes much longer than you think.
Finished – Spring 2018