The scaffolding is up and we have made a start.

As we will be installing 200mm of external wall insulation, the scaffold has to be erected in such a way that it can be easily modified to allow enough room to install the wall insulation and render at a later date. In practice, this means a scaffolding board or two closest to the house can be removed later, without having to re-do the whole scaffold.

The chimneys are coming down  – chimneys are not great if you are trying to make an airtight house. Luckily, ours are on the outside, so demolishing them is not too disruptive.

One big piece of work is to replace the existing suspended timber ground floor (joists and floorboards) with a new insulated concrete floor slab. The builder has taken the timber out and you can see the supporting “sleeper” walls below. The depth of the void under the floor varies quite a lot and follows the natural slope of the ground. It varies from about 450mm to 1100mm.

The reason we have done this is that it is very difficult to insulate a suspended timber floor without creating thermal bridges – every joist is a thermal bridge. The concrete floor will have 300mm of insulation (Expanded Polystyrene, or EPS) underneath it. True, the insulation is interrupted by internal masonry walls which are built off their own strip foundations – but we have a way of mitigating those thermal bridges – more later.