[quote author=JohnD link=1107609975/0#0 date=1107609975] I have been completing our rewire and there are several places where I have been chasing in wires where I have found that the plaster - though intact - sounds solid if you tap it but in fact it is not adhering to the wall. The house is a 1930's semi and the plaster is probably original as most of the decor, kitchen and bathroom were.
Is this what they mean by 'blown' plaster?
Is it sufficient to work some bonding in behind the old stuff and then plaster where I have chased out? [/quote]
Sounds like the house
we're I'm doing up. Yes the plaster has blown, the fact that it's not hollow just means it hasn't come away from the wall that much - yet. Our house had one really bad patch of blown plaster, so much that the whole patch moved 1/2", but when it came to removing the patch, the whole wall came down as well. It was easier to strip the plaster than strip the paper!!
I can't see how you could put bonding behind the blown plaster to fix it. I think you'll have to do what I have done and bite the bullet and re-plaster, or in my case drywall it.