does each coat of emulsion paint re-activate the coat underneath?

[zenonithus]

I'm painting my walls with contractor while emulsion. I notice that when painting over several previous coats the new paint seems to turn the dry paint underneath wet again?! So if I keep brushing in the same spot I'll eventually get back to the wall. This I find creates patchiness in areas. When I bash a wet area with the brush it scrapes off most of the layers underneath it as it they have been softened. Can anyone shed more light on this as I'm very new to painting with emulsion. Cheers.

 

[Nige F]

Contract paint has no vinyl in it - it's only used for "mist coat" on new plaster and on ceilings because it will do just what you're experiencing. You need a good quality Vinyl Matt and go over what you've done.

 

[zenonithus]

Ah ok thanks for the info. I initially bought it for the ceiling, though the walls had plastered areas and patches that were dark, so walls where very patchy. I used the contractor emulsion to give a white base to even everything out. I will then use a layer of grey clay paint over the top. Do you think the contractor emulsion underneath will hold up ok as a base as long as there is the layer of clay paint on top? Will I have the same issues painting over it with the grey clay paint (it melting!)? next time should I use a vinyl emulsion for the base? cheers

 

[chappers]

There should be no reason why you can't paint multiple layers of contract matt provided each coat has dried sufficiently and you don't over work it.
You can't use vinyls and silks as a mist coat. Are you painting on fresh plaster or maybe silk.
If fresh plaster then you should have first applied a mist coat(watered down paint) which will soak into the plaster and seal it, especially if the walls have been heavily troweled. If silk or even to a degree vinyl then you probably want to give it a sand to give a key for the matt emulsion

 

[zenonithus]

Hi, I'm painting on a wall that had a satin emulsion paint finish which I then covered with Gardz clear primer (it had wallpaper paste and pva on it which I tried to take off, hence the Gardz) I had to put several coats of the contract emulsion paint on to cover the patches so it's laid on fairly thick. I think I am trying to eliminate each patchy area with a coat when really the finish paint should be much thicker and give better coverage, so will probably stop with the contract emulsion coats is that correct?

 

[chappers]

depends what it is somethings cover better than others.

 

[zenonithus]

its delux vinyl emulsion, voc is around 10. I think its got pretty good coverage. I'm skimming some areas of the contract emulsion paint that rubbed off, with some fine surface filler to match the thickness. Though this stuff reactivates with water, so hope the matt vinyl gives enough water protection on top to stop that from happening.

 

[misterhelpful]

As mentioned, contract matt contains no vinyl and so will not dry to a film like vinyl emulsions do. It is designed to be used on new/porous surfaces which will allow it to be 'absorbed' into the substrate. As you have used Gardz, which is a sealer, it will have left an impervious barrier for the contract matt to adhere to properly. This is why you are finding it 'reactivating' and coming away.
The best thing you can do is use a vinyl emulsion, which will stick to the Gardz much better, but you may still have problems with the contract matt softening as you apply it on top. It could be worthwhile re-coating the wall with Gardz to reseal the surface if you do encounter those issues.

 

[zenonithus]

Thanks misterhelpful, yeah you're right the smooth water-tight barrier of the gardz is causing an issue with the contractor paint adhearing. It seems fine when dry, though when re-activated it is very difficult to keep it from smearing off. I need to try not to overwork areas. I have some grey vinyl emulsion for the top layer, I hope it's enough to seal as I'm fresh out of gardz. Though I would imagine the gardz would also re-activate it. I really need to post before I do big jobs like this :-\