Another mist coat

[eddieed]

Hi,

Currently decorating my bathroom and the old paint is pealing away, it is so bad that it is coming off in sheets like wall paper does and is returning to the bare plaster. What is the best way to continue before repainting.

Do I need to do another mist coat, or can I just paint as normal?

Should I use the bathroom paint (white anyway) for the mist coat or will any type of emulsion paint be ok?

Should I use a watered down PVA instead?

Thanks in advance?

Eddie

 

[misterhelpful]

Should I use a watered down PVA instead?

A word of advice...never ask that question here...it freaks us out!

PVA can cause all sorts of problems when painted over so never use it on a surface you intend to paint.

Use a contract matt, watered down by around 20-25%, for your mist coat and then an acrylic eggshell/bathroom paint as your finish coats. You can use vinyl emulsions for a mist coat but non-vinyls (contract) are much better.

 

[eddieed]

Thanks for that, just now need to strip all the paint off, this was meant to be a quick job and has turned into a nightmare!

 

[JohnD]

perhaps it is peeling off because somebody put glue on the wall before.

 

[EddieM]

well, no doubt this is one that causes many a disagreement and I can see why. Basically you need to counter the porosity of the new plaster. Nothing wrong at all and in anyway wrong with a mist coat. However a suitably diluted and unfortunately that is the key suitably diluted PVA coat will do the same, what you need to achieve is stopping the porosity but NOT coating the wall with what is effectively chewing gum and will in that case, peel. Both will work BUT with a mist coat you can't overdo it..... There that said, ducks and runs!

 

[misterhelpful]

There that said, ducks and runs!

GET HIM!!!!!!!

In all seriousness though, I have used PVA to seal in the past and was lucky enough never to have had an issue with it but, having encountered problems when others have used it, I stopped. I agree that it is down to the correct dilution ratio, and I remember saying so in some of my first posts here, but I now recommend that people avoid it like the plague. Unibond even print it on their cans/data sheets that it is unsuitable for use with water based paints. Mist coating is much more reliable, providing the water dilution is sufficient.

My turn to duck and cover!

 

[JohnD]

there are still a few people who recommend glue, but most of them have been beaten to death by angry decorators.