We highly recommend considering environmental options with all projects. The fibres in the hemp insulation (see above) are incredible strong enabling the baps to maintain their integrity when positioned. We use two types of diffusion open membranes on either side of the insulation allowing the house to breath which is strongly advised.
On the left Jon is mixing hempcrete which is hemp shivs mixed with a lime solution. The drying process may be long but the insulation becomes harder and harder as time goes by until it calcifies becoming stonelike with the air trapped inside.
Below we have used 50cm of Leca balls for the ground insulation. After pouring in the Leca it is then compacted with a 100kg compactor then covered with a fibre membrane. Steel mesh is placed on top to stabilize, then a concrete pad is laid in the standard way. No plastic!