We have a two storey house with walk out basement. We want to extend the main floor family room by approximately 10x12 and our renovator suggested a sono tube foundation - no basement underneath. We will get good storage underneath the new room (it will be approximately 6 to 8 feet above ground level) I wonder if the floor of the new room will be cold. How should this type of addition be isolated and heated? (we have forced air-gas) Any other thoughts or suggestions (other that putting in a full basement).
Answer:
About the only way it will be a warm floor is if you drop the ceiling in the storage area so that a heated cavity (crawl space) can be introduced. It doesn't take much, but the floor of the crawl space and its side walls have to be heavily insulated. A 4" duct can then be pant-legged into that area and the floor is warm.
