Our house has an addition that is circa 1970's. We will be renovating the room soon, and want to raise the floor to the height of the kitchen it attaches to. The subfloor/foundation of the addition appears to be poured concrete. From measuring I have determined that the floor in the addition could stand to be raised about 2 1/2" or so. The room will be gutted during the renovation. I need ideas for a new subfloor.
I was thinking about raising the floor with rigid insulation and plywood. We are in Wisconsin and it might boost comfort level in the room. If I did that what would be the best way to secure the rigid and the plywood to the original subfloor? One issue with raising the floor is that I will need to also raise the doors to match, but we are reframing anyway for a new patio door and windows.
Also, what would I put under the doors if I raised the floor? Continue with the rigid and plywood, or something beefier?