Paint flaking/coming away from wall

[philipb82]

Hello

I painted my house a couple of years ago using Dulux Matt White paint. Over the past few months I have noticed in three areas the paint has loosened and come away from the wall so I can just peel it off. Two of the affected areas are very small but one is fairly large. Its also left what I can only describe as a white residue/powdery substance on the floor. Anyway after searching on google I know that I have to scrape the paint away and sand. Would it be best to prime the bare plaster before applying the top coat? Also what could be causing it? The walls in question are interior, the plaster behind looks alright.

I hope someone can help. Its not a big problem but I would like to know what could be causing it and wil priming it solve it.

The problem is at the bottom of the walls just above the skirting board in all cases, if that helps!

Thanks

Phil

 

[LJW61]

The first coat onto plaster (or filler) needs to be thinned with 23-30% water otherwise it will peel/flake..
Do this on the affected area followed by a couple of 'neat' coats & it should be fine

 

[philipb82]

Thanks for your reply.

Will thinning the paint be just as effective as proper primer? I was going to go for Dulux trade all purpose primer.

Thanks

Phil

 

[LJW61]

Hi Phil, I presume youre painting the walls with matt emulsion? If so you wont need primer, thats only used on bare wood/metal prior to top-coating though it wont do any harm on the walls , just a bit of overkill

 

[philipb82]

Yeah its Matt emulsion. Thanks for your advice

Phil

 

[Setone]

i have this problem when painting onto new plaster. like the previous poster said watered down emulsion, or failing that use a bit of neat pva glue.

hope this helps

Paul

 

[roughcaster]

watered down emulsion, or failing that use a bit of neat pva glue.

I can see them all typing now,,,,,,,,,,,,,,, DON'T use PVA to seal new plaster before emulsioning,,, never,,, ever. Use a mist coat of watered down trade matt emulsion.

Roughcaster.

 

[Setone]

for a small area, i can't see what problem it would cause? i konw you need to let new plaster dry out so wouldn't dream of doing a whole wall / room etc but like i said i done it in tha past and had no problems.

 

[NickB_99]

Its also left what I can only describe as a white residue/powdery substance on the floor. ........The walls in question are interior, the plaster behind looks alright.

There may also be some hygroscopic salts being drawn into the plaster also from brick/block work underneath. The plaster will be sound, but these salts are possible. Normally very common in fireplaces for example, where fossil fuels have been burnt. Might be worth a quick post in the plastering forum too. May be some advice there how to cover if it is happening.


The other info provided in the posts with regard to the paint coming away due to not being diluted for first coat, I would agree with.

So you may have 2 things going on.