Insulate Under Bay Window Floor

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

Insulate under bay window floor.

In addition to floors other cantilevered architectural features may require insulation. 50 mm celotex bonded to plaster board. They include bay windows greenhouse windows bow windows bump outs porches and balconies. This type of window protrudes from the house while also letting in lots of light.

Buy this item from amazon uk. I am planning on insulating my 1st floor bay window using celotex or similar between the joints. Celotex pl4050 is a thermal insulated plaster board. Side walls also need insulating if no cavity exists.

This high performance thermal insulation board has 50mm of pir insulation. I have removed the plaster and lathe but now i have a question. The void between the joints drops down below the floorboard level and seems to be a void until just above the ground floor window. If the floor is over a garage and has not already been insulated however it is recommended that each joist bay be filled with insulation.

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. 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.

Also added 2 pics under the bay window showing the white vinyl siding 1 8 green foam sheet insulation brown lap siding heavily weathered white trim board and 1 2 white styrofoam. The smooth surface between the floor joists is cardboard laying loose on top of the t g flooring. To be used under bay window. No vapour barrier is required and the foam blocks a considerable amount of sound transmission from the outdoors too.