Help! Rescuing PVA glue stained skim plaster?

[mrburns2010]

Hi I'm after advice on how to successfully paint over newly skimmed plaster that has PVA glue streak stains running down it? Just to explain...

A relative (lesson now learned!) offered to re-skim our house and has done our kitchen and dining room up to now. Anyway the problem is that the ceilings were skimmed after the walls, and as a result PVA bonding glue has soaked down through the walls and created a 'streak' effect.
When we painted the kitchen, first with watered down emulsion, the streak effect came through on the paint where it couldn't be absorbed by the glue stains - and subsequent coats have just made it worse as the paint 'layers up'.

I'm guessing that there might not be much we can do for the kitchen now, especially as units have gone in and we are reluctant to do anything too messy. But we've not started the dining room yet, so is there any way we can prime the plaster here to cure this? We tried sanding the stains off, but the glue seems to have soaked deep thorugh the plaster. I'd therefore thought about sealing all over with watered down pva first - but have read in other posts that this is not normally recommended?

Would an oil-based primer paint work?

Or should we bite the bullet and get it re-skimed?

Many thanks for any help!

 

[Robbie uk]

You shouldnt need to to do anything as drastic as replastering. sometimes the PVA can be taken off with a blade and sometimes not. Give it a good sand down and apply a coat of oil based undercoat to the whole wall. When dry repaint in your chosen emulsion paint. This i think should do the trick.

 

[roughcaster]

I agree with Robbie's comment, good old undercoat will seal it in.

 

[mrburns2010]

Many thanks for the advice guys, I shall give that a go.

 

[Nige F]

Oil u/c on a whole wall Water based Zinsser for me

 

[roughcaster]

Oil u/c on a whole wall

Done that many a time Nige, on water stained ceilings, on old distempered walls etc, before pva/float/skimming them over. Also used it over whole ceilings, badly stained with nicotine. It seals in the stain wont wash off, and guarantees no stain bleeding through the emulsion or plaster. Never used Zinnser,,, the only downside with oil based is the smell, but i've left houses smelling nicer afterwards, than what they were before i went in,, fag fumes etc.

 

[joe-90]

Robbie is correct. Undercoat dries quickly so doesn't smell for that long.

 

[roughcaster]

Robbie is correct. Undercoat dries quickly so doesn't smell for that long.

Yep,,, never had a problem,, although I always tell the customer i'm using it first, just in case someone's allergic to the smell.

 

[nok1]

go for the oil base, the zinseer is pretty good but exspensive.
as for the plastering you do the walls 1st and then the ceilings so your not scraping any plaster splashes off walls/boards before you start. if you see what i mean.
but to honest the pva marks are a massive pain in the backside. even worse when they patch in the middle of a wall and put pva everywhere. a good rub out normally sorts it out but if not go with the undercoat

 

[hughmac]

My plasterer told me to lightly sand over the walls and then add one part PVA to the misting mix of 20% Water/ Emulsion. I have not misted yet as I want to be sure I have everything ready before I apply any paint at all!

When I sanded the walls I discovered lots of dry glossy PVA stains in wide strips along the join of ceiling and wall. I have tried everything from scraping to “wet and dry” (auto type) I can get it to come off with a scraper when I wet it. I have read the posts here and I wondered how things worked out for those asking for advice. Any feedback? How did mburns2010 make out in the end. Rughcaster I am thinking about covering the stains with Zinnser (too scared to use oil based undercoat …not that I doubt you…just windy). Is it best to cover all three walls and ceiling or just areas showing stains?

 

[Nige F]

My plasterer told me to lightly sand over the walls and then add one part PVA to the misting mix of 20% Water/ Emulsion. I have not misted yet as I want to be sure I have everything ready before I apply any paint at all!

?

Thank goodness for that You DON`T want PVA in any form or dilution on the plaster. Just go for the Water Based Zin - ask @ a decorators merchants Go over the whole room - I`ve just done a room with powdery plaster and it`s bound it back with no problems - then 2 coats of normal vinyl matt. job`s a good `un .

 

[Richard C]

My plasterer told me to lightly sand over the walls and then add one part PVA to the misting mix of 20% Water/ Emulsion.

You shouldn’t be sanding newly plastered walls before painting for a start; they should already be flat, smooth (but not over polished) & ready to go with mist coats & your chosen finish. Streaking your walls with PVA is slip shod clumsiness & if he’s if he’s told you to PVA before painting or add it to the mist coat then he’s a complete knob.

You don’t want PVA anywhere near a plaster you’re going to paint. You can scrape off the odd streak but if it’s bad, seal with water based Zinser as stated & next time get yourself a better plasterer.

 

[JohnD]

Ordinary PVA is water-miscible (that's why it turns to slime when you emulsion-paint it) so after scraping off any thick bits, wet and scrape it off. Try not to use a wet rag as this will just smear it. A mist sprayer should do.

 

[hughmac]

Thanks Nige F. I am glad I came on here first I dread to think of the consequences and the amount of damage I would have done had I mixed PVA with the paint.

Based on what you say this is my plan.

Because this problem has held me up I will now not have spare time to decorate for at least six weeks. There is a slight crack in the skim over a door frame where a stud wall joins a solid wall I will see how that goes over this period and watch out for other cracks at the same time, if no further cracks then on to the plan.

Plan
Scrape as much PVA off the surface as possible, back to bare plaster if I can.
I have already done a light sand on the whole area and most of it now looks smooth and clean. Some of the PVA must have been very diluted because it came off in light flakes with a few passes of a window scraper. One corner and ceiling/wall angles are heavy with PVA and it is rock hard.

I will cover the whole area of 700 Sq Ft with Water Based Zin (123?) as you recommend.
The following weekend I will do the first Emulsion Coat (Dulux Brilliant White Emulsion?) Not diluted
The next weekend apply the second coat.
The colour coat for the walls (going over the two coats of white emulsion) will give three coats on the walls.

Anything to be gained from using a “Tack Cloth” before the Zin or washing with a damp sponge?

 

[JohnD]

One corner and ceiling/wall angles are heavy with PVA and it is rock hard.

warm water spray and scrape off. Wipe the slime off the scraper so it doesn't smear back on the wall. You can use the same method to remove old paste and paper residue from an old wall you want to patch and paint.

The damp sponge is likely to just smear it on the wall.

BTW I agree with a couple of coats of matt white emulsion on the walls first before your finish colour. This will highlight any remaining blemishes to you so you can fill them, scrape smooth and re-emulsion with white to give the best surface you can do. A scraper is quicker and cleaner than trying to sand smooth, but do it before any filler is fully hard. You only need fine sandpaper if there any bubbles or flies legs stuck to the surface.