bubbling paint ... :-(

[Julian Fowler]

We're in the process of painting a bedroom, using one of B&Q's "New England" paints. The walls were previously painted with that looks like a vinyl silk, were clean and appeared sound before we started. When we put on the first coat, a small number of bubbles, 3-5mm across, started appearing on the walls - these could be "burst" with a finger or the point of a screwdriver, but left a mark on the wall.

The second coat, however, is *far* worse - within a few minutes of painting one section of wall, at least 50 of the same bubbles had appeared in an area less than 1m^2 :-(

I fear that the only remedy is to wait for the second coat to dry, sand down everywhere that the bubbles have appeared, and recoat.

Questions:

- any ideas on what the cause of this is?

- why would it be worse on the second coat than the first (1st coat had been on the wall for 48hrs before starting the 2nd)?

- how can this be prevented?

I have visions of the room being measurably smaller as a result of n coats of paint by the time we've finished :-(

Julian

[Dee]

Did you clean them (sugar soap & hot water) or do they just look clean. Sounds like residue on the walls is stopping the painting from sticking. If it is happening on second/third coats then it sounds like the earlier coats were not fully dry.

AndyP

[Julian Fowler]

Thats what I would have thought had the walls *not* been washed w/ sugar soap (they were), or the 2nd coat had been applied too rapidly (as I said in the OM, 2nd coat was applied 48hrs after the first).

The good/strange news is that at least of the bubbles from the second coat have now disappeared "of their own accord".

Julian

[Bob Mannix]

I think it was the previous decorator who didn't prepare the plaster walls properly. The original vinyl silk coat has patches of nonadherence, where the plaster was greasy or something. When the moisture from the new paint gets into the old original layer, it is expanding and coming away. On drying it's pulling back in again. You get a similar effect on lining paper which looks sound but properly pasted wallpaper appears to bubble on it - it's actually the lining paper lifting. If it's pulled back in, it'll probably do!

[Lawrence]

Lawrence

usenet at lklyne dt co dt uk

[Julian Fowler]

Based on many other "features" of the house, as modified/decorated by previous owners, this sounds highly likely!

Looks like there are still some spots where the "bubbles" are staying put as the paint dries. However, its not *nearly* as bad as it was when the 2nd coat was first applied - maybe to the extent of just being imperfections that are acceptable in an old house :-)

Julian

[Julian Fowler]

Its a barn conversion, so age is a little difficult to determine. The walls/basic structure are at least a couple of hundred years old; however, the conversion to residential was done in 1979, and there's no evidence of any of the interior plasterwork or decoration being any older than that.

The existing paintwork looks like standard late 20th century emulsion!

Julian

[Barb]

I had this problem in an old 1930's house on a ceiling - I think it was old whitewash or something. I ended up rubbing it down and putting on a coat of white undercoat - the sort you use under gloss paint - which adhered fine. Then a coat of emulsion.

I was a bit desparate with it, like Julian, and was prepared to try anything. And it worked.

Barb