The footings in the buildings are rammed earth tyres. At the front of the building, the tyres are three deep below the ground, where by the right side (by the door) they are one or two deep. The depth of the foundations was dependent on the surface they were being built on, so I had to dig down to ensure I was building onto solid soil. Around the foundations, I installed a french drain to ensure no water gathered around the base of the building.
Once the foundations were placed, the retaining wall was built up from the back with a waterproof membrane behind it to stop the moisture coming through the wall when it rains.
I reinforced the wall with iron rebar every other tyre. The rebar was placed every second tyre after four courses (one below ground) and then again on the final course ensuring the iron was going into the tyres which weren’t reinforced on the previous course.
To finish the wall, a wall plate was built with a ladder style which provided a moisture barrier between the tyres and the straw – just in case any moisture manages to creep up through the wall!
Inside, the wall is still exposed tyres at the moment, but I will plaster over this, possibly using hempcrete, like Rik Lander did in his straw bale studio (see here)
As I plastered the outside of the shed, I realised that I had an excess amount of lime render, so I have done some test patches to see how well lime render sticks to my tyre wall. I’ll report back on this in a few weeks once it has dried and set. If things go well, I will do the whole wall and post up a method on it.