Hi guys , this is a strange one and any help or advice would be much appreciated . Me and my mate roughed and skimmed inside a council property last year sometime after it had been underpinned and treated for damp. . A couple of months ago we had to go back to hack off and re do some of the walls as they had blown or cracked .now these weren't ordinary cracks , some were quite big and the woman even said one or two had pulled the wallpaper apart because she was watching t.v at the time and heard it.now we have to go back again next week to re do another wall. There's also ceiling upstairs and walls that have cracked that we didn't even plaster . The engineer has been out and hacked a bit off, his verdict was that we used too much sbr and then he said that we weren't timing it right then he said it was reacting or something . Now we always do things this way and never had another call back before . We were thinking that the engineer just looking for some one easy to blame and to keep the woman quiet to just repair the walls instead of digging deeper ? Doesn't every one use sbr inside ? I prefer it to pva as it pulls in quicker and ready mixed ? Is there any does and donts with sbr inside ? Thanks guys for any help