1930's Bay window insulation help

[Chutch84]

Hi everyone,

Need a little help from the community on how best to undertake this job of attatching 37.5mm foil backed phenolic insulated plasterboard to the timbers of my bay window while limiting thermal bridging and degating the job of the foil as its acting as a vapour barrier. Should i use any special mechanical fixings aswell as PB adhesive? what products are well suited for this particular application? Sould i mitre the edge of the plasterboard to butt up nicely in the corners or leave square and pu foam the joint?

Any advice greatly appreciated.

 

[blup]

Use a suitable spray foam and tape over. If you mechanically fix to the frame, consider using a nylon plug to screw into to minimise transfer of damp/cold it’s an Achilles heel though.

 

[turpis]

I wouldn't overthink it. A few normal screws straight into the stud aren't going to make a spot of difference to the insulation's effectiveness. That's what the manufacturers recommend.

Mitre / foam depends how much time you've got on your hands!