Dekers Posted July 3, 2019 Author Report Share Posted July 3, 2019 12 hours ago, Paddy Galore! said: the underlying layers of paint are usually very thick when this happens, when you put a fresh coat on it's putting moisture into the existing paint, where the existing paint hasn't adhered to the wall surface properly it causes a blister, this usually happens with eggshell or silk finishes. this will carry on happening to the affected area. I've treated walls with oil based undercoat before and it's helped as it forms a barrier stopping moisture ingress through the paint layers, you need to let the wall dry out completely, pop and scrape back the blisters, re treat the pock marks with the oil based paint, then fill and rub down, then oil based undercoat, then final emulsion, you don't need the red Zinsser, it stinks to high heaven and is very expensive, if you or any of the household have breathing problems then don't go near the stuff, you could try the yellow Zinsser, it's oil based and is a bit easier on the lungs, contrary to what's been mentioned earlier you can put emulsion over undercoat, it's an old trick of the trade for covering and sealing stains. atb paddy That was very much my thinking, and unfortunately tends to confirm there may be some work to deal with this properly! Quote Link to comment Share on other sites More sharing options...
Paddy Galore! Posted July 3, 2019 Report Share Posted July 3, 2019 20 hours ago, Scully said: I agree oil based paints are good for killing stains, but not as good as Zinsser, which also comes in white incidentally, but I wouldn’t advise painting an entire wall with oil based paint if it is to be topped with a water based emulsion. It will stick, for a while, but eventually cracks will begin to show in the emulsion as the underlying oil paint underneath dries much slower, similar to the craquelure effect you see on old oil paintings. I don’t understand how it’s possible to put moisture back into an existing paint layer once it has dried? osmosis, silk and eggshell paints are micro porous and absorb some of the moisture, as the fresh paint film gets a skin forming the trapped moisture goes back through the existing paint to the wall and then forms a blister, over worked plaster, oil and silicon based sprays and furniture polish are the main causes which basically comes down to bad prep or sabotage, and yes, red Zinsser is the dogs danglies for forming a barrier coat but it's overly expensive for a simple thing like blistering paint. a simple barrier coat of the cheapest oil based primer or undercoat thinned out will do the job just as well. hi dekers, you have several options, you could re plaster, slurry coat with easyfill, or use lining paper, these will introduce more moisture to your wall so you will still need to do the prep with a barrier coat. or use a barrier coat of oil based paint and fill the pock marks, how much you spend is up to you, I can recommend Zinsser in the yellow tin which is oil based, or polycell stain block which is also oil based. I can also recommend the cheapest, nastiest, oil based undercoat or primer you can find, all the above paints will take a while to dry thoroughly but will give you a decent base to start again. cheers, gram Quote Link to comment Share on other sites More sharing options...
Scully Posted July 3, 2019 Report Share Posted July 3, 2019 23 minutes ago, Paddy Galore! said: osmosis, silk and eggshell paints are micro porous and absorb some of the moisture, as the fresh paint film gets a skin forming the trapped moisture goes back through the existing paint to the wall and then forms a blister, over worked plaster, oil and silicon based sprays and furniture polish are the main causes which basically comes down to bad prep or sabotage, and yes, red Zinsser is the dogs danglies for forming a barrier coat but it's overly expensive for a simple thing like blistering paint. a simple barrier coat of the cheapest oil based primer or undercoat thinned out will do the job just as well. hi dekers, you have several options, you could re plaster, slurry coat with easyfill, or use lining paper, these will introduce more moisture to your wall so you will still need to do the prep with a barrier coat. or use a barrier coat of oil based paint and fill the pock marks, how much you spend is up to you, I can recommend Zinsser in the yellow tin which is oil based, or polycell stain block which is also oil based. I can also recommend the cheapest, nastiest, oil based undercoat or primer you can find, all the above paints will take a while to dry thoroughly but will give you a decent base to start again. cheers, gram I find it hard to believe it's the paint, it's more likely the plaster which is porous, or 'honeycombed', like I suggested, and also like I said, one option is to coat it with a sloppy mix of filler, as you have also suggested. You don't need red Zinsser as it comes in white, like I also suggested, which is just as effective, and it also comes in aerosol for ease of use. It isn't that expensive. Quote Link to comment Share on other sites More sharing options...
vampire Posted July 3, 2019 Report Share Posted July 3, 2019 The house I decorated only had one wall affected and we painted whole house,it was coated with this horrid red paint and I believe its this that caused the blistering,we popped sanded and filled mist coat on bare filler the full coat,it cured it 99%. Ronseal do a 'damp seal' I always have tin of this on the van blots out most things if stain block doesn't work.stir it well and ventilate Quote Link to comment Share on other sites More sharing options...
vampire Posted July 3, 2019 Report Share Posted July 3, 2019 On 01/07/2019 at 20:37, bear-uk said: I've got this problem in a tenanted house that was fully re plastered and its looking like the salt from the old brickwork seeping though the dot dab and plaster and creating solid bubbles like yours and some started going moldy/furry. Recommendations are take paint off back to plaster and paint with an oil based undercoat to seal it before top coating. You could try damp seal,paint it over wider area than affected as the tide will spread as it cant breath the area could get bigger. Plasters should of stuck insulated plaster board to the wall which would be a damp barrier and prevent thermal bridging of the dabs bleeding damp/salts. Quote Link to comment Share on other sites More sharing options...
Dekers Posted July 4, 2019 Author Report Share Posted July 4, 2019 Got to get on so embarked on a course of action last night. Results in a few days! Quote Link to comment Share on other sites More sharing options...
Paddy Galore! Posted July 4, 2019 Report Share Posted July 4, 2019 14 hours ago, Scully said: You don't need red Zinsser as it comes in white, like I also suggested, dude, it's the colour of the tin not the paint the red tin is shellac based, yellow is oil based, blue is water based and useless Quote Link to comment Share on other sites More sharing options...
Scully Posted July 4, 2019 Report Share Posted July 4, 2019 Ah with you! I wondered why you kept going on about ‘red’ zinsser, and why I’d never come across it! 🙂 I’d agree the water based one is useless as a stain blocker, but a very good primer for most surfaces. Have never used the oil based Zinsser, apart from Zinsser All Coat, which is an excellent paint, even the water based one. Just for general information for those interested, the oil version of All Coat stinks to high heaven, like nail varnish, even outside, so I always plumb for the water based one. Quote Link to comment Share on other sites More sharing options...
Mice! Posted July 4, 2019 Report Share Posted July 4, 2019 And no one has mentioned the aero advert! Quote Link to comment Share on other sites More sharing options...
Dekers Posted July 5, 2019 Author Report Share Posted July 5, 2019 (edited) Latest. The bubbles are from the paintwork BELOW the paint I am applying and it is evident the paint is not adhering to the walls in these specific areas. The bubbles do not go away when the emulsion dries! However, I have pushed them flat with the back of my fingernail and they seem to stay in position quite well. I cannot believe how abrasive matt emulsion is, I have worn away 2 fingernails to paper thin!!!!! 2 coats of oil based undercoat have been applied to the walls in the effected areas and the bubbles did not re-emerge. I have just applied a coat of emulsion over the areas and it works, no bubbles have emerged! The down side is I have found 3 more areas where I didn't apply undercoat and they have bubbled, so the saga continues, but a solution is at hand, however unprofessional it may seem! Edited July 5, 2019 by Dekers Quote Link to comment Share on other sites More sharing options...
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