Hi I've got two areas that are cantelevered out of two rooms about two feet by 9 feet. The floor joist are 2x12 and the underneath is just covered with vinyl siding on the outside.You can access this area from the basement where bat insulation is in place.Problem is there is air leakage entering this space and the floor above(hardwood) gets quite cold even though there is a floor register right under the window.Would removing the bat insulation and having soft foam sprayed in to fill the cavities work?This would be about twenty cu.ft of foam per window.
is there currently insulation under the extended area?
Yes there is some fiberglass insulation and some tar paper acting as a vapour barrier but the tar paper isn't really properly installed and the cavity is about half filled with the fiberglass insulation. You can feel the air penetration when there is any wind blowing outside.