new paint cracking as it dries.

Postby geezer15 » Sat Feb 27, 2010 12:43 pm

Knowing how much I hate decorating (I'm the kind of guy where everything goes wrong and I have no patience any more). My wife (who loves me decorating and thinks I have nothing better to do) has had a bedroom skimmed so all I had to do was paint it. The plaster was left to dry for 4 days then wallpaper paste put on to seal it a week later. I have now painted it, using a roller and dulux, light and space, emulsion. As it dries the paint has cracked like crazy paving. I have used two different tins of the same type/colour paint and both have cracked so I guess its not the paint itself (both new tins and not stored anywhere.
I am happy the walls were dry befor starting so does anyone know 1) whats wrong and more importantly 2) How do I put it right. (cant really afford to get it skimmed again and get a painter in but I think I will end up doing that.)
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Postby stoneyboy » Sun Feb 28, 2010 7:40 pm

Your first coat of emulsion should be well watered down, I suspect you applied the paint straight from the tin and the dry walls are sucking the water out of the paint, hence the cracking.
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Postby theshedman » Sun Feb 28, 2010 7:45 pm

Hi geezer, you should have sealed the walls with a mist coat of watered down emulsion not wallpaper paste. While the paste is on the walls there is no way you will get a decent finish. Wallpaper paste should only be used to seal walls if you intend papering them. If you want to paint them then you are going to have to get rid of it somehow. Try mixing warm water with a bit of washing up liquid and brush this on a bit of the wall leave for a little while then see if you can then scrape it off. If it comes off do this to the whole wall and give it a good wash down afterwards to get all the paste off. If this doesn't work you could try sizing the walls again and put up lining paper then emulsion over that. Would seem a shame to do that on nice new walls though. Let us know how you get on or want more advice. Good luck.
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Postby chris_on_tour2002 » Sun Feb 28, 2010 10:56 pm

good advice but i'd replace the washing-up liquid with table salt - much more effective at shifting wallpaper adhesive.
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Postby theshedman » Mon Mar 01, 2010 8:04 pm

Hi chris, as geezer has already painted the walls I said about the washing up liquid to try and loosen the paint. Then he should be able to use the salt. Could be a long job to get off though depending on how the emulsion has taken.
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Postby geezer15 » Sun Mar 07, 2010 8:53 pm

OK so how am I getting on?
Well I didn't fancy taking all the paint off and couldn't see the point in lining paper and then painting- might as well just wall paper.
So I sanded the walls fillied the cracks and painted again. Guess what- the paint cracked. So I filled sanded and painted with a watered down mix (suggested by a local painter and decorator) but it cracked again, all be it less so.
So Guys you are right and I am lazy! I am now stripping off the paint using a steamer 3 walls down 1 to go (the biggest). Will then wash the walls etc and mist coat. Will let you know how it goes. Nothing worse than someone asking for advice and then not taking it eh!
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Postby geezer15 » Sat Mar 20, 2010 12:26 pm

Final Result:
Well I have just finished the 3rd and final coat of emulsion. It looks fine:).
I looked at the finished walls, after stripping and saw quite a bit of damage to the 'new' plaster's surface. Obviously there were some marks where I had caught the plaster with the scraper but mostly the top suface had come away with the paint and was slightly pitted in places. I spent some time filling and sanding (getting good at that now) filling and sanding again.
I then sealed the surface properly. I tried to follow one of the recipies Ive seen on this site somewhere ie 60% emulsion 35% water and 5% PVA. Well my measuring jug could n't cope with 5 of anything so I mixed a blob of PVA with about 400 ml water (didnt mix too well, had to fish out some lumps of PVA but it was an old container) and about 500 ml of paint was added to that. Anyway I had a litre of goo when I'd finished, whatever the formula was. It went on fine. left it a couple of days to dry and then painted. I left each coat at least a day, even though the container said I could do a 2nd coat after 2 hours. I wanted to make sure it was dry properly and didn't crack again.
Happily it didn't and its finished - all be it 3 weeks later than expected. Thanks for your help.
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Postby geezer15 » Sat Mar 20, 2010 12:34 pm

Oops forgot to mention I did wash the walls down with salt before sealing. I then rinsed the walls down with water a couple of times as I wasn't sure how the salt would affect the sealer or paint. Then left to dry for a couple of days.

I have no idea how professional painters and decorators work- I seem to work for a couple of hours then have wait for days for things to dry before I can move on- I'd never make any money at it. Ha Ha
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Postby theshedman » Sun Mar 21, 2010 10:05 am

Hi geezer, glad to hear that it came out right in the end. Personally I would have missed out the PVA as I don't like using it on walls as it sometimes causes bubbles in the paint similar to wallpaper paste but in very small amounts it would probably be fine. The main thing is that you now have a finish that you are happy with.
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Postby thedoctor » Sat Jul 06, 2013 9:11 am

Guys, lots of tips and tricks here for dealing with paint faults and other stuff. Decorating tips and tricks, thats what we like!!
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