Painting Newly Plastered Walls

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A quick on here - in a coupld of weeks (when SWMBO is away), I will be painting the newly re-skimmed walls in the living/dining room and kitchen. Obviously I know I need a mist coat etc. However, over the past week or so, a couple of people have said to run decorators caulk along all the corners.... One person being SWMBO step-dad and the other being the guy who has done most of the work (but not the skimming).

Now all the DIY sites I've been reading in regards to mist coats etc have never mentioned caulking the corners - so this has had me thinking. Is it really necessary? I understand the purpose of what they are saying, but if the DIY sites don't mention it, I'm thinking it's not an absolute must. Afterall, wont adding caulk (even the tiniest, thinest bead) kinda ruin the sharp corners and almost "round" them off?
 
paint walls first,I use a cheep white matte for first coats, it helps to seal the walls and shows if there is any thing to be filled or bits that will need sanding or blobs that are not seen after the plasterers have finished, then chalk skirting boards and architrave , but never corners of room.then apply your coloured coats.
 
If you use decorators caulk it will eventually dry out and shrink. Far better to use silicone, I own a sealant company and we seal all internal windows, door architraves and top/bottom of skirting boards. Only trouble with silicone is that to certain degree you get one chance to do it right.
 
we have had 4 rooms skimmed and all i did was use b &q cheap as chips white emulsion did a couple of coats then used the colour i wanted
 
bensherman2 said:
If you use decorators caulk it will eventually dry out and shrink. Far better to use silicone, I own a sealant company and we seal all internal windows, door architraves and top/bottom of skirting boards. Only trouble with silicone is that to certain degree you get one chance to do it right.
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Forgot to say we seal everything on the finished walls, glossed/varnished skirting.
 
bensherman2 said:
If you use decorators caulk it will eventually dry out and shrink. Far better to use silicone, I own a sealant company and we seal all internal windows, door architraves and top/bottom of skirting boards. Only trouble with silicone is that to certain degree you get one chance to do it right.
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What do you use to stick paint to the silicone?
 
You have to paint the gloss or emulsion first as you can't overpaint most if not all silicones. However there are some "modified" sealants that you can paint.
 
So you end up with a shiny line down the corners.

We used to use Texas own brand Painters' Mate along the top of skirtings, round architraves etc.. We'd smooth it off with a finger or something else to get it pushed well into the gap then go over it with a moist paintbrush to get it as smooth and flush as possible. Close to 30 years since I did this room and it hasn't cracked or pulled away from the surfaces it was applied to.
 
No you don't get a shiny line as the silicone cures matt. These days especially in construction sites chippies use no-nails or nail guns to attach the woodwork and because there's generally no heating in whilst they are being built once the heating goes on the wood will shrink. So gaps will appear along the top of skirting boards etc.
 
Nod said:
So you end up with a shiny line down the corners.

We used to use Texas own brand Painters' Mate along the top of skirtings, round architraves etc.. We'd smooth it off with a finger or something else to get it pushed well into the gap then go over it with a moist paintbrush to get it as smooth and flush as possible. Close to 30 years since I did this room and it hasn't cracked or pulled away from the surfaces it was applied to.
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tight git,,,get it decorated :)
 
It was done properly when I did it all those years ago so still doesn't need redoing.
 
We've had a couple of rooms replastered. Never had to caulk the corners. In fact you could be giving yourself more work by doing it as the decorators caulk I bought from Screwfix doesn't like being overpainted. In a couple of places where I've used it it has left a cracked finish once I put paint on it ( close inspection of the fine print says this happens sometimes).

I would just do a mist cost of emulsion thinned 25% with water, sort out any filling or sanding that the mist coat shows up, then do your top coats.
 
The cracking of the paint happens when you overpaint it before it's properly dry and cured. Overnight gives it enough time to go off properly. Proper preparation is the key to good (and lasting!) decoration.
 
old walls repllastered?
should not need any work as such, i would just give them 3-4 days to completely dry first though.
 
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When we had an extension built a couple of years ago I used a B&Q trade paint especially for new plaster and never bothered with a mist coat and it was fine.
 
I always use a weak pva mix to prime new plaster before painting- never silicone before painting as paint will just run off it. If you use silicone bear in mind you will have to remove it in the future if you re-decorate.
 
stevetiler said:
I always use a weak pva mix to prime new plaster before painting- never silicone before painting as paint will just run off it. If you use silicone bear in mind you will have to remove it in the future if you re-decorate.
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Not necessarily, if you put a bead on top of skirting for example you can apply masking tape and cut in. Good thing with sealant is that it won't crack.
 
bensherman2 said:
Not necessarily, if you put a bead on top of skirting for example you can apply masking tape and cut in. Good thing with sealant is that it won't crack.
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Agreed ! I'm a big fan of silicone- I get through tubes and tubes in bathrooms and you are right when you say it wont crack
 
Nod said:
The cracking of the paint happens when you overpaint it before it's properly dry and cured. Overnight gives it enough time to go off properly. Proper preparation is the key to good (and lasting!) decoration.
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Good advice about the proper preparation, it takes 'forever' and losing the will to live happens.
Once properly dry and prepared apply a thin coating of PVA before you start the decorating.
(IMO overnight is not long enough for plaster, even a skim, to dry naturally, even on a dry Summer night).
 
Mr Bump said:
old walls repllastered?
should not need any work as such, i would just give them 3-4 days to completely dry first though.
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I'd leave it longer than that to dry out. The plasterer who skimmed our walls said to leave it 2-3 weeks, minimum, before painting.
 
Mag1cp2x said:
Good advice about the proper preparation, it takes 'forever' and losing the will to live happens.
Once properly dry and prepared apply a thin coating of PVA before you start the decorating.
(IMO overnight is not long enough for plaster, even a skim, to dry naturally, even on a dry Summer night).
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The overnight drying was/is for the painters'' mate/ decorators' caulk rather than the plaster.
 
Why oh why do you want to caulk the corners??? Never ever seen or heard of that one before :thinking: of course unless the new plaster skim is crap then I still wouldn't do it(n). Definitely along the tops of skirting board and along architraves. Also run a bead of silicon along the bottoms of skirting board/ floor. this helps to stop any dust/ dirt marking new carpets especially light coloured ones ( got that tip from a carpet fitter)
 
Plastering was done 4-5 weeks ago (total project has been 5 weeks). Won't be painting until end of the month as swmbo will be away on holiday with the future MIL
 
If only you had given the plasterer the tins of paint before he added water to the powder eh. ;)
 
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