Today we are showing how we are making a panel of the hempcrete floor. Using several different layers to create a warm and dry environment.
As a first layer we have used 5 cm of gravel, then we put an impermeable, breathable membrane on, then a 5 cm layer of expandable clay aggregate balls and then the actual hempcrete.
We are using a mix of hempcrete (lime, water and hemp fibre) with sand, to make it stronger. It makes the mix more compact and solid, so that it is more load bearing.
We had some problems when we started with the floor before with the material that we put in directly underneath the hempcrete. We initially wanted to use expandable clay aggregate balls, but we were persuaded to use hemp pallets (compressed hemp fibre with linseeds). They have more thermal mass and therefore insulate better than the clay balls. But what we found is that with the wetness of the hempcrete on top, it disintegrated and absorbed so much of the humidity from the hempcrete that it got mouldy.
So we had to take up the whole floor, and start over!
Fortunately, with a material like hempcrete, it is possible to reuse most of the material that normally would have gone to waste. What we did, is mixing it into the new hempcrete mix and using it as the first layer and finishing off with "fresh" hempcrete for the levelling of the floor.