Expanding foam to stick plasterboard patch to brick?

[Mander]

I've got a small area in my bathroom (under the soil pipe) where there is no plasterboard or tile, just brick. There's a small gap to the outside.

I bought a can of "exact gap" spray foam with the intention of filling the gap, but I also want to put in a plasterboard patch, then a tile, skirting, and a pipe collar. Can I use the foam to attach the plasterboard to the brick? The rest of the wall is dot and dab so it sticks out a bit from the brick.

 

[^woody^]

Yes, if you secure the board to stop it being pushed out while the foam expands. Mist the wall and back of the board first.

 

[mcprinter]

I have used foam specifically for plasterboard. Works well.
You squirt onto the board and leave for a few minutes.
Mist the board and wall with water as Woody says

This seems to be a low expansion foam so might well be ok.
Don’t use too much or you will be fighting it