Paint not adhering, what is happening?

OldKettle · 22 Oct 2017

Hi,
I have recently painted a number of rooms with a matt emulsion, without problem. However, in one room the paint is not adhering well, almost like the surface is non-stick. After leaving the paint for 15 minutes, it can easily be scraped off with a fingernail.

The wall was previously painted, but I don't know what paint was used. The problem happens all over the walls, but is worse in certain patches. I have attached a couple of pictures.

What is happening here? Can I solve this by washing the walls down and priming before trying to paint them again?

Any help would be much appreciated.

Jadele · 22 Oct 2017

lol what are you using mold paint? this usually happens if the wall is damp so its not drying. you could try doing a weak pva mix on it then painting it.

Lower · 22 Oct 2017

Do not use PVA under paint under any circumstances.

Jadele · 22 Oct 2017

Lower said:
Do not use PVA under paint under any circumstances.

Use his advice instead, oh wait he has none but he can use google at least. A weak pva will bind up any loose surface allowing your paint to bond it not ideal but in the circumstances.

it maybe that it has been coated thick in pva and thats why it aint sticking.

Lower · 22 Oct 2017

PVA will just make the situation worse.

Jadele said:
Use his advice instead, oh wait he has none but he can use google at least. A weak pva will bind up any loose surface allowing your paint to bond it not ideal but in the circumstances.

it maybe that it has been coated thick in pva and thats why it aint sticking.

So you recommend putting more PVA over the PVA that might be the cause of the problem?

Logical.

I would use one of the Zinsser products as a sealer/primer.

Jadele · 22 Oct 2017

Lower said:
PVA will just make the situation worse.

So you recommend putting more PVA over the PVA that might be the cause of the problem?

Logical.

I would use one of the Zinsser products as a sealer/primer.

weak as in barely there yeah. but thanks to google for zinsser product recommendation.

ps not dogging your rec just the fact that you did mine without offering anything and only on questioning have you put forward anything of value
, turns out that product could be good if it does as it claims.

OldKettle · 23 Oct 2017

Thanks for all of the input.

Having read further, it seems that PVA is definitely the problem.

I have also read that the PVA can potentially be washed off, and also that I could use an oil based undercoat.

I really only have one shot at painting this room in time, so would the oil based undercoat be the most surefire way of fixing this?

Nige F · 23 Oct 2017

Bite the bullet and use a Zinsser product. Oil undercoat is not surefire

Lower · 23 Oct 2017

I've used Zinsser bin when a plasterer had sloshed pva over the walls when he'd skimmed the ceiling. It worked for me but it was covering smallish areas.

Zinsser have a good technical support helpline. I'd speak with them and let them advise you on what product to use as a primer/sealer.

opps · 23 Oct 2017

Jadele said:
Use his advice instead, oh wait he has none but he can use google at least. A weak pva will bind up any loose surface allowing your paint to bond it not ideal but in the circumstances.

it maybe that it has been coated thick in pva and thats why it aint sticking.

I decorate for a living and have to say that your advice makes little sense. If the wall were damp PVA wouldn't dry. PVA also reactivates when wet, hence it shouldn't be used when painting or tiling.

Plasters apply PVA to both reduce the level of suction and to "glue" the plaster to the substrate. Tilers use SBR (which is not weakened by moisture), painters add water to counter suction.

I don't doubt that your post was well intentioned but it is bad advice. Sorry.

misterhelpful · 23 Oct 2017

Jadele said:
weak as in barely there yeah. but thanks to google for zinsser product recommendation.

ps not dogging your rec just the fact that you did mine without offering anything and only on questioning have you put forward anything of value
, turns out that product could be good if it does as it claims.

Untitled

misterhelpful
24 Jul 2014
1

mattylad · 23 Oct 2017

I'd sugar soap wash it all down, get that rubbish off then Zinsser bin it.

But then I'm not a decorating expert so what do I know....

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Paint not adhering, what is happening?

Similar threads