Insulate Under Bay Window

50 mm celotex bonded to plaster board.

Insulate under bay window.

Celotex pl4050 is a thermal insulated plaster board. Bay windows are one of the more complicated window styles to install but their impact is well worth the effort. This type of window protrudes from the house while also letting in lots of light. I ve written quite a few articles on how to insulate basement walls and floors but one more specific topic related to this subject keeps coming up and that s how to insulate a bay window floor or cantilever floor framing.

Buy this item from amazon uk. The problem of having cool floors under bay or bow windows and alcoves is a very common one. Either way filling the floor cavity with spray foam delivers excellent thermal insulation while also keeping drafts out of your bay window area. The rim joist under the window appears to have only the 1 8 green foam vinyl and lap siding covering it no other insulation.

Bay window and floor deck cantilever insulation details. Because it is difficult to properly insulate and air seal these areas without filling the cavity getting sufficient heated air in to warm these areas during the winter months can be tricky. Side walls also need insulating if no cavity exists. No vapour barrier is required and the foam blocks a considerable amount of sound transmission from the outdoors too.

To be used under bay window. I recently found the styrofoam under the bay was only press fit in some areas no fasteners held up by a friction fit on the back side of the lap siding. Most people only insulate under the bay window. I have a bay window in my kitchen facing south that gets very cold on the floor during the winter months.

I want to insulate outside under the bay but fiberglass insulation is too thick as i only have 1 1 2 between the bay ceiling to the bottom of the siding. And the farther a bay window protrudes from the house the more dramatic the effect and the more it opens a room.