Insulating bay window upstairs and ceilings

[noseall]

Top job that mate, did you push down the insulation boards down the gap between floorboards

Yes, if there are no obstructions. There are two layers also. One fitted between and the other across (in front) of the studs. The window board was fortunately deep enough to not need replacing.

 

[mcprinter]

I did my 1930s bay last year. Hanging tiles and no felt. Lath and plaster wall.
Insulating has made a real difference. Boarded with foil-backed plasterboard (my Plasterer recommended)

Have seen some vids/pics where the timbers are built out into the room to allow for thicker insulation.
Might be worth considering?
Would obviously need a new, deeper window board.

 

[cdbe]

Have seen some vids/pics where the timbers are built out into the room to allow for thicker insulation.

Don't do that, just causes cold bridging - better less wood and more continuous insulation.

 

[mcprinter]

Don't do that, just causes cold bridging - better less wood and more continuous insulation.

I may have misunderstood what I saw. Or maybe a dodgy DIYer!

 

[thediyer]

Yes, if there are no obstructions. There are two layers also. One fitted between and the other across (in front) of the studs. The window board was fortunately deep enough to not

So I finally removed the battens going across and had a look if I could push the boards down and I have no obstructions, its 430mm length stud to stud. The height is 1200mm (gap from under the floorboard to the window)⁹.. im thinking to cut the boards around 435mm to squeeze them in for a tight fit and then tap them down with a rubber mallet...

I will seal gaps near floor boards and studs with expanding foam (if required) cut the excess dried foam and then stick the foil tape across the studs and boards...only thing I won't be able to do is tape the studs and boards under the floor boards as I wont be able to get my hand down there..this should be an issue right?

Also the width is only 70mm from the felt to the end of of the studs... and I know Insultation boards only come in 50mm or 75mm so I think I'm just going to get the 75mm pack them in they insulation boards will stick out ..but i will screw in foiled back plasterboards with larger drywall screws.

Also is an air gap needed ? Although out side there is hanging tiles with and 20mm gap and then older style roof felt (picture attached) some of the felt came away and u can see the tiles behind it
(Sorry for the 100 questions I just want to get it right lol)

 

[thediyer]

Forgot attach picture