Insulate Under Bay Window

The problem of having cool floors under bay or bow windows and alcoves is a very common one.

Insulate under bay window.

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. Either way filling the floor cavity with spray foam delivers excellent thermal insulation while also keeping drafts out of your bay window area. Buy this item from amazon uk. 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. Bay windows are one of the more complicated window styles to install but their impact is well worth the effort.

Bay window and floor deck cantilever insulation details. Outside under the bay is open. Side walls also need insulating if no cavity exists. 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.

Most people only insulate under the bay window. And the farther a bay window protrudes from the house the more dramatic the effect and the more it opens a room. This high performance thermal insulation board has 50mm of pir insulation. No vapour barrier is required and the foam blocks a considerable amount of sound transmission from the outdoors too.

In this article i ll share a detail for new construction and also a detail for renovating existing 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.