Protecting the footings from frost

In this climate, the footings have to be buried four feet deep to avoid being affected by the frost. Whilst this is currently the case for the outside of the building, most of the inside footings are exposed as they will eventually be inside a heated house and only a few inches below floor level. The problem here is that whilst there is no heat in the building there is a potential for the gound under the footings to freeze and create frost heave which could move the footings and buckle the foundations. To avoid this, I have covered the footings over with a four inch thick layer of polystyrene board and also a layer of mineral wool insulation that will eventually be re-used to insulate the walkout basement wall. Also, the ground drains very well as it has lots of small stones and is therefore less likely to accumulate water that can cause frost damage. Now that the roof (sub-floor) is on it will also help to keep out some of the cold. So hopefully, everything should be fine until Spring. There is still a lot of snow inside the house, but it will also act as an insulator and will just melt away in Spring, unless I can be bothered to shovel it all out before then.

The pile of wooden posts will eventually support the timber frame above it and help support the ground floor as the current supports are temporary. The posts are 10" square maple sourced locally and are nine feet long which is the height of the basement walls. They still need to be planed and oiled.