Bathroom paint keeps cracking and won't adhere next to shower

[Matthew32]

I feel like I've written about this a million times, but here goes....

When I moved in my property 8 years ago, I had tha bathroom retiled and the bathroom wall replastered. It's an exterior brick wall in a victorian house.

It then transpired the tiles were fixed directly to the plaster, with no membrane or waterproofing (it's a bath shower), so the tiles were leaking water.

I've since had the wall tiled again, with a water proof membrane (sheet, not painted), and that problem is now fixed.

However, over the past few years, I've had a persistent problem with the wall next to tthe shower, not holding paint, and bubbling/cracking shortly after it's painted. It just all scapes off with a scraper.

Nothing seem to adhere to it. I've had a tile removed and the tiling checked to to make sure its not letting water through, and it's been checked for damp. I've redone and redone and redone the paint work over and over again, filled it, primed it, and painted it. I was using Matt emulsion, but even with bathroom paint, the same thing happens.

Someone said to me it could be the salt in the plaster.

There are no pipes in the wall, the shower comes from the bath taps which come up from the floor, I've had it damp checked, I've had the tiles installed with a membrane and rechecked. I've left it days and days before repainting again. Each time the paint cracks and buddles, and just chips off with a scraper.

I'm at a lost, but need a solution. The only thing I haven't checked are waste pipes from the flat upstairs, that go through that wall at the top (pictured)

Any ideas?

 

[stevethespreader]

you shouldent need tanking or a membrane if the tiles are on sand and cement undercoat what was the bathroom replastered with?

 

[Matthew32]

I’ve not sure. It was a sort of blaster. Sand based.

 

[stevethespreader]

i would def take that back to brick and see whats what

 

[wwwebber]

I replied in a similar way to your other post. This is a groundfloor room and thus you may have existing / historical damp in the wall which will result in your bricks & plaster being "infected" with salts. The only way to cure this is to take it back to brick and use plaster treated with damp / salt retardant.

The waterproof membrane you installed around the bath is masking the damp but not curing it.

 

[bobasd]

the cause could be that the tile has been stopped just under the enclosure stile ie at the edge of the bath - the tile should have gone beyond the enclosure stile by a tile width.
and best if that tile width had been dropped down to the floor.
water might be penetrating behind the stile and then spreading out by capillary action and gravity.

remove the enclosure jamb from the wall and look for water penetration.
make sure its only been siliconed on the outside not the inside.
lower the shower head if its too high.
then hack off back to masonry about a tiles width beyond the edge of the bath.

when making good dont use gypsum plaster, use a 3:1 mix of sand and lime - rub up the finish with a float.

from the pic of the outside wall and its plumbing arrangements everything looks pretty DIY which makes me wonder about how professional the inside work has been?

FWIW, i once had to return three shower enclosures on the spin to the shed - each one leaked in turn. eventually the customer said she would live with it.