Plastering On Painted Walls

[fishstick]

I am currently renovating an older house in Chiang Mai. I have currently got the Burmese builders in plastering my previously painted walls. Before work started we tried to strip the paint however this wasn't so successful, being concerned that the new plaster will not gain a bond with the old painted wall surface we then proceeded to run horizontal cuts into the wall at 2 inch intervals so the new plaster would at least have something to get a grip onto. Anyway the inside of the house is now nearly finished and my worst fears are coming true the new plaster has started to crack and come away from the walls.

Any help or advice will be appreciated. Most of the plaster will have to be scraped off and I guess I will have to start again. Maybe I should have PVAed the wall first. Anyone know what the local brand is and what I should ask for at the hardware store??

[wilsongbrown]

I am currently renovating an older house in Chiang Mai. I have currently got the Burmese builders in plastering my previously painted walls. Before work started we tried to strip the paint however this wasn't so successful, being concerned that the new plaster will not gain a bond with the old painted wall surface we then proceeded to run horizontal cuts into the wall at 2 inch intervals so the new plaster would at least have something to get a grip onto. Anyway the inside of the house is now nearly finished and my worst fears are coming true the new plaster has started to crack and come away from the walls.

Any help or advice will be appreciated. Most of the plaster will have to be scraped off and I guess I will have to start again. Maybe I should have PVAed the wall first. Anyone know what the local brand is and what I should ask for at the hardware store??

When I had my damp and soggy walls replastered in the UK, the plasterer did indeed coat with PVA first to stop the old plaster falling into and spoiling the new render, so it shouldn't be any different here.

PVA Everywhere here in thailand from small plastic bottles to large tubs. Every hardware store knows what PVA is. It's also written in roman script on every container. In short, you must use PVA anywhere in the world to coat old plaster before re-rendering. Hope this helps.

Edited October 8, 2009 by wilsongbrown

[Bucko]

I am currently renovating an older house in Chiang Mai. I have currently got the Burmese builders in plastering my previously painted walls. Before work started we tried to strip the paint however this wasn't so successful, being concerned that the new plaster will not gain a bond with the old painted wall surface we then proceeded to run horizontal cuts into the wall at 2 inch intervals so the new plaster would at least have something to get a grip onto. Anyway the inside of the house is now nearly finished and my worst fears are coming true the new plaster has started to crack and come away from the walls.

Any help or advice will be appreciated. Most of the plaster will have to be scraped off and I guess I will have to start again. Maybe I should have PVAed the wall first. Anyone know what the local brand is and what I should ask for at the hardware store??

--------------------------------------------------------------------------------------------------------------------------------------------------------------

When I have had to do that sort of a job here in NZ---I hire a small electric jack-hammer that can have a small steel " comb-like " tip fitted--and rough up the whole area.

Then got a decent plasterer who did not have a problem----should be done in 2 coats---- cover/render coat first to iron out all the lumps and bumps---then when dry-a skim/finish coat to get it up to a paint finish---never seen PVA used as a key---but suppose it would help the cause.

The render and skim---are 2 different plaster types

Also it may be possible that your guy put it on far too thick---and is falling off under it's own weight.

Hope this helps------Bucko