Insulate Under Bay Window

Outside under the bay is open.

Insulate under bay window.

Either way filling the floor cavity with spray foam delivers excellent thermal insulation while also keeping drafts out of your bay window area. Bay window and floor deck cantilever insulation details. Buy this item from amazon uk. 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.

No vapour barrier is required and the foam blocks a considerable amount of sound transmission from the outdoors too. Bay windows are one of the more complicated window styles to install but their impact is well worth the effort. 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. 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.

The rim joist under the window appears to have only the 1 8 green foam vinyl and lap siding covering it no other insulation. Celotex pl4050 is a thermal insulated plaster board. To be used under bay window. 50 mm celotex bonded to plaster board.

This high performance thermal insulation board has 50mm of pir insulation. And the farther a bay window protrudes from the house the more dramatic the effect and the more it opens a room. Most people only insulate under the bay window. In this article i ll share a detail for new construction and also a detail for renovating existing bay window.

I have a bay window in my kitchen facing south that gets very cold on the floor during the winter months. Side walls also need insulating if no cavity exists.