In my last post I discussed spray foam insulation in the walls and ceiling. The same technique was used for the floor. Here’s what the floor looked like after framing but before the insulation was applied:
Here’s the floor after applying the insulation:
Yes, it looks just like the walls look. The foam insulation does dry solid, but it is full of tiny air pockets, so you don’t want to walk on it, since you will likely compress the air pockets and lower the insulation value. That’s why we applied the plywood floor as soon as possible:
Yes, this picture also shows the drywall on the walls, but that’s the subject of my next post.
{ 2 comments… read them below or add one }
I do not understand why you are insulating the floor. The floor provides cooling in summer and heat in winter, so why do you want to impede the heat transfer to or from the basement floor? It seems to me that by insulating the floor you are guaranteeing a reliance on your cooling system, rather than fully taking advantage of what mother nature is offering you.
Good question. You are correct. The ground does moderate the temperature, so perhaps you are correct that it shouldn’t be insulated.
In my case, I insulated because I want a consistent temperature. By the end of the winter the ground is presumably very cold, and by the end of the summer it would be much warmer, which could cause temperature fluctuations. By preventing heat transfer in or out, I maintain a stable temperature. Yes, I’m reliant on my cooling system, but with proper insulation and a reasonably full cellar, the cooling system is not always on. In fact, there are days when I don’t hear it at all.
In addition, it’s not just the temperature you need to worry about; there is also humidity. I want consistent humidity. In the spring, as the ground thaws, considerable humidity could be released into my cellar; that’s why most people’s basements are damp. The insulation helps keep humidity levels consistent.
That being said, if you could build your entire cellar deep enough that the top of the cellar was a few feet below the frost line, you wouldn’t need any insulation at all; that’s how all of the old wine cellars work.