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).
I didn’t get around to finishing-off the render right up to the final purlin / roof joist at the front of the house. This left a small gap which I figured I could stuff with straw and render as part of the general finishng-off process. Some wrens have taken advantage of my tardiness and turned this gap into a winter roost. I say ‘some’ – when I was out yesterday at roosting time (16.40) I counted 15 going in in a 5 minute period. I reckon there most be at least 30 in all bedding down there every night. Now, I don’t really want to fill it in, although come the spring they will probably all move out, although some may try to nest there. I should probably therefore try and make some roosting / nesting boxes since it would be nice to have some resident wrens.
I have now finished putting in all the windows (sort of). Putting the frames in was very quick and easy, however painting and then glazing them was a real pain. Each window comes with glazed panels held in place with wooden beads tacked in with a couple of panel pins. You have to take these out to screw the windows into the sub-frames, but in putting them back in you need to put sealant strips around the glass, plus fill the voids between the units and the frame with industrial quantities of silicone sealant. This probably takes almost an hour per unit.
I decided to simply tack the units back in place in order to get the building weather tight and will do the fiddly permanent glazing later. None-the-less, it has probably taken as long to get this far with the windows as it took to put on a coat of render.
Next job – flooring.