What’s causing this paint to blister

[kevnick80]

Hi guys

about two years ago, I got my bathroom remodelled. The tradesmen (I think they were used to doing bog-standard work whereas my project was a bit more complex) removed all the previous tiling then put up some marble tiles.

It seems to be that where they plastered over the removed tiles (and other parts of the walls) the paint has started to crack and bubble and blister.

Any ideas how to sort it and what could have caused it in the first place so I can get it sorted?

Thanks.

 

[Dangee]

Can you send better photos in relation to the room. None of those photos indicate it’s in a bathroom

 

[conny]

Damp under the paint. When they removed the tiles they probably gave the wall a scrub down with something, (possibly chemicals to remove old adhesive), then washed it down to remove any chemical traces. They haven't waited for the wall to dry out thoroughly before painting.
Don't know the best way to solve it other than strip it all back, clean the walls with sugar soap and allow to dry out properly before using a stabiliser on the plaster. Let this dry and then apply a few mist coats before finishing with a top coat or two.

 

[kevnick80]

Damp under the paint. When they removed the tiles they probably gave the wall a scrub down with something, (possibly chemicals to remove old adhesive), then washed it down to remove any chemical traces. They haven't waited for the wall to dry out thoroughly before painting.
Don't know the best way to solve it other than strip it all back, clean the walls with sugar soap and allow to dry out properly before using a stabiliser on the plaster. Let this dry and then apply a few mist coats before finishing with a top coat or two.

Thanks Conny.

Sounds like a big task but at least I know what has to be done. I will get someone on this.

 

[Dangee]

What is the other side of the wall? It may have always been an issue, you just didn’t realise coz of tiles covering it up.

 

[securespark]

Could be damp tracking through from outside?

 

[Dangee]

Pictures are very vague

 

[securespark]

If you take a palette knife and scrape off the loose paint, does the plaster underneath look darker (ie damp) than an area where the paint has not blistered?

 

[kevnick80]

If you take a palette knife and scrape off the loose paint, does the plaster underneath look darker (ie damp) than an area where the paint has not blistered?

the wall doesn’t look darker and doesn’t seem damp.

Here are a few more photos.

the wall is on the side of the close wall/stairwell outside. This is on the other side.

 

[JohnD]

they might have applied PVA. After scraping off the paint, scrub it with hot water and wipe off the residue sludge with an old towel. Do not leave it to re-form on the surface.

There are still some plasterers who like PVA, but most have been killed by angry decorators.

 

[Dangee]

That’s way I queried the other side of the wall. The damp line is angled, like a roof line or staircase. If it’s an external staircase, could need some water proofing. I don’t think it’s much if it’s taken two years to get like that. Maybe they could of sand cement rendered before skimming but personally, I’d make sure your extractor is up to the job or get one with a humidity sensor, remove paint where necessary, use an aqua block,repaint.