My son recently had work done in his basement due to water seepage. What they did was install new weeping tiles but from the inside and they installed a water proof membrane on all the walls and leading into the weeping tiles. A new floor was poured. My question is as follows: He wants to insulate it with a 1 1/2" strerofome insulation and then place the wall studs, do we bring the insulation to the floor? and do we place a vapour barrier and if so how far from the floor?
Answer:
With that system, he's looking for problems as time goes on. Insulation should never go all the way to the floor. When insulating any below-grade masonry wall it is best to build (in place) a 2X4 structure with studs 16" O.C. and pull it an inch and a half from the wall in order to accommodate R-20 fibre insulation bats without compressing them. The insulation actually goes from the sub-flooring above to within eight inches of the concrete floor and the 6mm polyethylene vapour barrier goes two inches lower so it can be pinched and stapled to each side of each stud. This keeps the insulation bats from sliding down and at the same time, the system avoids a lot of condensation problems. It also permits a bit of heat loss to the drainage tile along the exterior perimeter of the footings. In areas where frost is a problem, it is important that drainage at this point not be impeded.
