Insulating Bay Window

[JimE1982]

Hi All

First post here and having read some of the other posts on bay windows, I do have one additional question.

The bay window in the front bedroom has a timber frame, with render on the outside and plaster inside. The radiator is on the wall on the bay window - if that makes sense.

The room is very cold and road noise is very off-putting.

My plan is to remove the radiator and plaster board. Install additional studwork which will allow for additional insulation but also provide a window sill.

I plan to use slab wool insulation first and then foil coated foam (Kingspan or similar) and then plasterboard over the top.

The reason I am think slab wool as well as foam is for the noise reduction...my question is at what point should I use a vapour barrier? should I use it between the outside wall, then wool, then foam??

Any help would be appreciated.

thanks

 

[JimE1982]

bump

 

[Deleted member 292770]

no need for a vapour barrier.
create new studwork.
sit your slab wool inside it.
bond the kingspan to the studs and foil tape the joins. board over with screws long enough to go through the board and insulation.

 

[JimE1982]

no need for a vapour barrier.
create new studwork.
sit your slab wool inside it.
bond the kingspan to the studs and foil tape the joins. board over with screws long enough to go through the board and insulation.

Thank you! I've just removed the floor boards to cap the rad off and the void beneath the floor is huge - nearly two foot! As suspected though, behind the plasterboard is simply black felt and then on the outside would be the render. No wonder it sounds loud...