"Kev" wrote in message
ps.com...
I have made a deep chasing into a wall to take 2 copper pipes for CH.
If I fill this with expanded foam will plaster stick to the foam. I
had thought about putting plaster board over the void and filling with
foam as a backing for support but I might be able to dispense with the
PB.

Kevin


No it wont,why put PB over the void? why not just slap the plaster in there
when you're plastering it?