Hello!
I've torn out the entire moisture-damaged floor and will lay a new one in a room on the ground floor. The rest of the house will be done later as well. The floor joists will also be new. The old floor joists varied in height up to about 185, with a width of about 65. CC varied around 650...
In the new floor, I would like to add a bit more insulation, as well as underfloor heating, without affecting the height of the floor. The plan is to lay new joists 45x195 with CC 300 (span width 4.20 room width 4.60). It will be a regular tongue-and-groove wooden floor.
The problem is that the bottom of the joists will be below the top edge of the concrete foundation. Just a few centimeters, but still. It would also be nice to be able to add battens on top of the joists for the underfloor heating and its plates, but then I would need to lower the joists an additional 22mm.
Is this a "big no no," or can I do this? The space against the ground is good, and I'm simultaneously digging out some and laying plastic. The foundation is insulated on the outside with foam boards with plaster on top. It was also insulated with glass wool (!?) on the inside of the foundation, which was buried about 30cm in the ground... Odd solution. I have removed this because it was, of course, damp.
If I can build this way with lowered joists, how do I seal the joint between the subfloor/joists and the wall to ensure moisture resistance?
I've torn out the entire moisture-damaged floor and will lay a new one in a room on the ground floor. The rest of the house will be done later as well. The floor joists will also be new. The old floor joists varied in height up to about 185, with a width of about 65. CC varied around 650...
In the new floor, I would like to add a bit more insulation, as well as underfloor heating, without affecting the height of the floor. The plan is to lay new joists 45x195 with CC 300 (span width 4.20 room width 4.60). It will be a regular tongue-and-groove wooden floor.
The problem is that the bottom of the joists will be below the top edge of the concrete foundation. Just a few centimeters, but still. It would also be nice to be able to add battens on top of the joists for the underfloor heating and its plates, but then I would need to lower the joists an additional 22mm.
Is this a "big no no," or can I do this? The space against the ground is good, and I'm simultaneously digging out some and laying plastic. The foundation is insulated on the outside with foam boards with plaster on top. It was also insulated with glass wool (!?) on the inside of the foundation, which was buried about 30cm in the ground... Odd solution. I have removed this because it was, of course, damp.
If I can build this way with lowered joists, how do I seal the joint between the subfloor/joists and the wall to ensure moisture resistance?
It works well, as long as the space underneath is sufficient, and the ventilation is not covered. The best approach is probably to build up the blindbotten at the end so that there is some air between the foundation and the wood. Either as a small box or a sloping surface at about 45 degrees.
Great! Thankslarsbj said: