Interior plaster blown

[Alistair young]

After a recent watch spanish holiday TV programme the guy had half his plaster in upstairs bedroom chopped off because it had "blown". Builder said that damp was being transferred from outside and separating the sand cement render to the bricks and proceeded after the chopping of old render to coat the walls with PVA which in itself not waterproof but is a good adhesive. Considering where this guy lives gets at least 300 days sun a year and bedroom was upstairs I doubted that it was damp but inside walls were powdery. Wondered what anyone thinks?

[jayc89]

We had a section blown on an internal wall, I suspect it was down to the suction not being controlled properly. We have quite old, porous walls, and the plasterer used bonding and a couple of coats of multi-finish. He did have PVA with him, but I don't know if he used it on the areas we had problems. I suspect it needed something like hardwall rather than bonding to get the suction under control before the finish coats. 

 

All needs knocking off and doing again. 

Edited January 13, 2023 by jayc89