Ideas for how to finish off?

[theflyingpig]

Hi all. I've got an internal opening through a thick stone wall. I've built a frame to plasterboard sides and help out the aging lintels, but need to finish to the old plastered wall.... As you can see in photos it's, er, far from plumb!
Will filler stick to expanding foam? Could I potentially shape the foam and then fill?
Any other ideas gratefully received!

 

[cdbe]

Are you trying to straighten the adjacent walls? In which case D&D them. Otherwise just run the plasterboard past the edge of your frame, trim to the wall profile and foam a bit of plasterboard into the gap. You can get plasterboard external corner tape if you need something more flexible than the metal stuff.

 

[theflyingpig]

Great! Thanks. No, not trying to plumb up walls so your advice sounds spot on.

How would I fix formed bit of plasterboard in?

 

[thomp1983]

I'd cut a square vertical line down the plaster either side of the opening to reveal a decent bit of stone (a foot either side should do it).

With the stone revealed and cleaned I'd cut a bit of plasterboard that will run flush to the corner of your wooden frame, pack the frame out so you can screw the plasterboard flat to it and then use the following to stick the other part of the board to the stone work.

Soudal Genius Gun Plasterboard Adhesive Foam

Soudal Plasterboard Adhesive Foam is a fast curing replacement for traditional mortar adhesives. Use it to fill cavities and for bonding plasterboard to walls. You'll find that this foam is suitable for use on all common materials such as concrete, stone, plaster and wood.The adhesive comes...

www.toolstation.com

Id probably put a couple of screws in the plasterboard into the stone at the edge where it meets the old plaster just to stop it expanding out too far.

 

[theflyingpig]

Top advice! I'll give it a go.....