I am now tackling the last big, messy, inside job – sanding down and coating the floors. I have a deadline of the end of this week because that is when furniture is arriving from Ikea. I debated about staining the floor boards to try and give them more of an aged and weathered feel, but decided to preserve the ‘integrity’ of the material by keeping it natural, even if it does look a bit clean and Scandinavian.
I am not sure you ever get to a point where you say ‘it’s finished’. The last two months or so have been filled with finishing-off tasks: fitting or making doors and door frames, installing the kitchen, painting, installing lighting – nothing of particular interest from a straw building perspective but hugely time consuming non-the-less. I have estimated that the man hours dedicated to the windows (installing, painting, glazing) have probably equaled the time spent actually raising the walls.
In terms of passing on advice, I would say to not underestimate the amount of time required to do all this stuff.
However, today a sort of milestone was passed because it was the day I moved the tools out and put them back in the workshop. Up until this point I have had an OSB sheet set on trestles covered in tools, screws and bits and pieces as well as random bits of wood and board distributed about the place – so it very clearly looks like a work in progress rather than a nearly finished project. But now, while there are still a few things lying around, it looks closer to a space which is waiting for furniture (and also sanding the floor, which is the last big job that remains to be done). I feel I can now say that the project is almost finished – just some snagging jobs and, of course, the sanding and finishing of the floor. It will be done by Christmas.
We have just fitted the door. This was actually a very simple task (using the same company as supplied the windows), however it represented an important psychological milestone. Whilst your door is a sheet of OSB you don’t really have a house, you have a building site. It also means that we have a proper air-seal so it makes sense to light-up the pellet boiler – an important step forward given the sudden plunge into autumn.
I am now putting in the finished flooring on top of the chipboard sheets that sit on top of the joists. I have decided to go for scaffold planks. The problem with most conventional flooring products is that they all look too perfect (as well as being pretty expensive if you want solid wood as distinct from a laminate). For a project such as ours you need to have a floor that looks suitably rustic – and scaffold boards do just that.
Scaffolding Direct sells new, unbanded boards in various lengths, which work out at a cost at around £14 per square metre. This will give you a chunky 38mm, 23cm wide, board. The boards will obviously need to be sanded and finished, but the look is so much more solid and attractive. Interestingly, the price of new boards is about the same as recycled ones and since both would need to be sanded and the used ones are more likely to be damaged, as well as having bands on the end that would need to be removed, buying new seemed a better option.
I am nailing them down, rather than screwing them, because I think boards like this need to have visible nails to look suitably authentic. I would like to have used cut nails, but this won’t grip into the chipboard, so I am using good old ringshank nails. I got boards in lengths of 2.4m so as to get a good number of joins, since I think this also is a better look. I expect to get a little shrinkage over time, but this shouldn’t be a problem because big boards like this look better (more authentic if I may say that again) with slight gaps between them.
We have now refined the process. First up, I have decided to abandon using the render gun to apply a 10mm coat of 1:3 clay to sand mix in the first pass. The reason for this is that, as good as the gun is, the sand I am using has too many rogue 10mm stones in it, which block up the gun and the time I was saving was used up by frequently having to unblock it. If you have a better-graded (but therefore more expensive) mix this would not be an issue. Instead I am using the gun to put a clay slip-coat on – reverting to the technique recommended in the holy book. Putting this coat on with a gun is very fast.
We have also experimented with the mesh, working this into the top of the first / main, 20mm coat. Once this is on it is possible to ‘move’ the render around underneath it and flatten things out because the mesh stablises the surface. However, having discussed this with Chris from Back to Earth he recommends not putting the mesh onto the first coat, but rather allowing this to dry somewhat and then put the mesh into a 10 – 15mm top coat. We will try this from now on. I have also decided to add straw into the first coat, despite not necessarily needing this with the mesh, on a belt-and-braces approach.
I have also worked out a good way to get hessian to stick onto the wooden window sub-frames – namely to make a glue from flour, clay and water.
Finally I have made up a batch of ‘sticky straw’ to build-out around the windows. Since this involves creating a layer at least 50mm thick, this is too much for a render layer – even with lots of straw in it. Instead this is more like a very straw-rich cob. I used a mix of around 1 part flour, 2 parts clay and 2 parts sand – plus quite a lot of water and sufficient straw to get a mix to a point where the straw readily sticks together and forms a sticky, maleable material.
Last week my brother-in-law (who is a proper builder) and sister came across for a couple of days to tackle the drains and also the studwork for the bathrooms. Drains are relatively simple, but given it is so important to get them right it is very useful to have someone who knows what they are doing to set them out properly. The electrician also came across – so in the space of a day and-a-half the the drains were put in, the flooring was finished, the studwork for the bathrooms (the only internal walls other than straw) was put up and first-fix electrics was done.
It has just remained for me to chase-in the electrical conduits and secure the switch and socket boxes into the straw. The chasing was best done with a claw hammer and the boxes were secured using hazel pins about 30cm long as massive rawl plugs (see picture). These provided a reasonably firm fix – but I wouldn’t use them for fixing anything too large or heavy to the walls. For things like kitchen units I will probably revert to chasing 4×2 uprights into the straw and fixing these to the floor plates and then screwing horizontal batons into these. (Note the picture shows the boxes and conduits as the electrician left them – they are not secured into the straw).
For holding the conduits in place I used some smaller hazel pins and put a bent nail into the end and hammered these into the straw beside the conduit (see picture).
I have also had to prepare one corner for the installation of a pellet boiler. The view from HETAS is that you need a fireproof plasterboard and a 12mm air gap between this and the straw – so to be doubly sure I rendered the corner with one coat of lime, then put a 2×1 frame onto this, screwed top-and-bottom into the ring beams and also secured against the straw using hazel pin rawl plugs and then attached the fireboard. Final job to do here is make a hearth out of quarry tiles and we will then be ready to get the pellet stove in – which will provide heat and be very useful for helping dry out the clay plaster (next big job).