6. The Insulation Layer

Entrance dry? Chimney dry? Great! Let’s start building the next layer – the insulation layer.

What you’ll need:

  • Some clay
  • Some wood shavings
  • Some water
  • A bucket
  • A wheelbarrow
  • A spade
  • A power drill and plaster mixer (optional)
The insulation layer complete.

The insulation layer complete.

First thing you are going to do is make a clay slip which is simply clay mixed with water. The simplest way to do this is to put some water in a bucket and slowly add chunks of clay, squashing, squeezing and mixing with your hands as you go. Alternatively you could add water to half a bucket of clay and leave it to soak for a couple of days. You could then squish-up the clay quite easily.  You are aiming for a consistency similar to that of thin natural yogurt.  

I spent quote a long time making my slip until I discovered a short-cut method using a drill and plaster mixer. It works really well but is very messy! Chuck your clay and water in a large bucket (or large bin) and blitz it with the mixer.  Job done!

Next throw some wood shavings into a wheelbarrow. I bought a huge bag of wood shavings from a local pet shop and I still have three-quarters left (any takers?). Add some of the clay slip and mix well with a spade or get your hands dirty. The mixture should be wet enough to form “bricks” similar to those you made for the clay-sand layer.

Build up the insulation layer using exactly the same technique as before. Simple! Leave it to dry and then you can move on to the last step in the build – woo hoo!