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Old 19-03-2007, 12:32
aquazi
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I'm hoping some wise person can answer this for me.

I bought a 1930 semi last year. I stripped the nasty wall paper and got the walls re skimmed, which was done about June last year. I left about 2-3 weeks for the walls to dry before painting them, mostly in Dulux and Crown paint.

However now a lot of my walls have tiny hairline cracks in them. I can paint over them to cover them up, but why are they appearing? It happens a lot around walls that i have drilled into to various wall features, however it has also happened to a lot of my walls that i havent fixed anything onto. And the walls downstairs are all fairly solid brick, and i dont slam any of my doors (hardly use internal doors!)

Could it be the quality of the plaster used? or possible the house movement? Or is this something that happens and that i should live with it?
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Old 19-03-2007, 12:55
horseychick28
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Hmmm..when you painted the walls originally, did you use a watered down coat first? I know that if you don't then it can cause the plaster to crack. When we had ours done we watered down the first coat of paint with about 10-15% water (you don't need much water).

Sorry I can't be of more help, if worst comes to worst then you'd have to paper over them I guess...
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Old 19-03-2007, 13:01
Manko
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Could also be the mix of the plaster. If it dries too quickly it will crack. When we had our house plastered, the plasterer told us this in casual conversation.

He also did say, as above, that the first coat of paint onto fresh plaster needs to be watered down.
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Old 19-03-2007, 13:23
jon8769
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You should also paint a newly plastered and dry wall with an acrylic sealer before painting to avoid cracking probs too I think.
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Old 19-03-2007, 13:45
Cstar2229
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We use watered down wallpaper paste to seal it
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Old 19-03-2007, 13:48
duckapluck
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Our plasterer advised that we use pva bonding to seal the bare plaster.
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Old 19-03-2007, 14:14
sinead6uk
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this has happened to us too. it happens more in older houses apparantly something to with with the age of the walls and damp etc. really annoying though!
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Old 19-03-2007, 14:25
aquazi
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Thanks for that guys.....

I did use a water down version first to seal it, however i didnt bother buying those special plaster sealer that you can get from homebase wicks etc.

Do you think it would make a difference if i applied another coat to the walls now? It would hide the cracks, but then realistically i cant repaint my walls each yr! Took weeks to do it first time round!


Originally Posted by sinead6uk
this has happened to us too. it happens more in older houses apparantly something to with with the age of the walls and damp etc. really annoying though!
Have you just learnt to live with it? Maybe i'm just being picky but i find it quite annoying... the worst is on my landing, i have a crack from the floor up to the ceiling, which i notice everytime i go up my stairs
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Old 19-03-2007, 17:36
seacam
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Originally Posted by aquazi
I'm hoping some wise person can answer this for me.

I bought a 1930 semi last year. I stripped the nasty wall paper and got the walls re skimmed, which was done about June last year. I left about 2-3 weeks for the walls to dry before painting them, mostly in Dulux and Crown paint.

However now a lot of my walls have tiny hairline cracks in them. I can paint over them to cover them up, but why are they appearing? It happens a lot around walls that i have drilled into to various wall features, however it has also happened to a lot of my walls that i havent fixed anything onto. And the walls downstairs are all fairly solid brick, and i dont slam any of my doors (hardly use internal doors!)

Could it be the quality of the plaster used? or possible the house movement? Or is this something that happens and that i should live with it?
Hello Aquazi,
Gosh where does one start on your question.

There maybe several causes but the clues I think are in your thread., you don't say if the affected walls are stud walls or solid, stud I suspect if upstairs.

Plaster as used in the 1930s wasn't so much a much better quality plaster more it was layed on thick but it does have a shelf life.

You had the walls plasterer skimmed a common approach as long as the existing surface is in sound condition, by that I mean the existing plaster is not breaking down, something this is not always evident.

It is possible the plaster used for the new skim was old but I don't think so, it's a swine to work with, most plasterers won't use it, certainly any plaster we use is as fresh as can be.

Another strong possibility is the old wall paper paste is coming adrift from the existing plaster or interacting with the new plaster, this is why it is so important to rub walls to be skimmed down, so so important, sealing an old plaster finish is not the answer, rub down first, then seal.

Many many people make mistakes with new plaster and after three/four weeks apply their standard paint.

To late in this case but for the next time, new plaster should be allowed to dry naturally, if plastering is done in very hot weather, keep the room cool, ( close the curtains ), allow as much time as you can to pass before painting, certainty 6 weeks, much longer if you can, one of the reasons for this, is all new plasters skims can shrink and crack so there is no point in say, painting a ceiling, if it has to be done again.

In cold weather never use central heating to dry a room, just have patience, as soon as surface is dry, turn on CH to that room if you have to

The first thinned coat of paint to new plaster is to do with absorption/sizing nothing else, it won't prevent cracking of plaster and the first coat must be allowed to dry thoroughly.

If we have large rooms to do, it is not unusual for us to apply three coats.

Never, ever, ever apply uni-bond/PVA or some such sealant to new plaster----ever.

Standard emulsion to new plaster is never a good idea, there are wall paints for new plaster, it's as easy to apply but much more permeable and that's the secret to an eventual good finish.

All new paint/plaster must be allowed to breath and dry, sometimes up to 6/8 months after the new plaster is applied, before you can use standard emulsions.

So, I think what's happening to your walls is either you have used standard emulsion paint to soon after the skim or you say you have done a lot of drilling or something is interacting with the plaster skim.

It may simply be the old plaster finish has vibrated, moved/cracked and what your seeing is as the old existing plaster starts to break down or crack it is showing through the new plaster skim, this is not unusual, the fact that it hasn't happen to areas you haven't drilled, is fortunate and may never happen.

All houses move, thin plasters skims will be surceptible to this movement.

Have you done any harm,--no,is there something you can do about it,-- may be but you must do it before hot weather.

There are several brands on the market, available almost anywhere, basically it's a very thick paint and it flexes, it is designed for hairline cracks and I mean hairline, can't tell you how many people use the stuff in the hope it will cover cracks.

I would suggest if you go down that route, to rub the affected walls down lightly to get a key,( do do this), then apply, let it dry 5/8/10 days before repainting.

Word of WARNING, if the original existing plaster is breaking down, this work around will work but will not cure the problem for ever if at all.

Re-skiming walls is a standard effective approach for many householders, in most cases it works just fine and resolves lots of issues-----up to a point, however if one is after a blemish free smooth plastered finish forever on existing 70 year old plaster,----- it's not going to happen.

Last edited by seacam : 19-03-2007 at 17:39.
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Old 20-03-2007, 10:15
aquazi
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Originally Posted by seacam
Hello Aquazi,
Gosh where does one start on your question.

There maybe several causes but the clues I think are in your thread., you don't say if the affected walls are stud walls or solid, stud I suspect if upstairs.

Plaster as used in the 1930s wasn't so much a much better quality plaster more it was layed on thick but it does have a shelf life.

You had the walls plasterer skimmed a common approach as long as the existing surface is in sound condition, by that I mean the existing plaster is not breaking down, something this is not always evident.

It is possible the plaster used for the new skim was old but I don't think so, it's a swine to work with, most plasterers won't use it, certainly any plaster we use is as fresh as can be.

Another strong possibility is the old wall paper paste is coming adrift from the existing plaster or interacting with the new plaster, this is why it is so important to rub walls to be skimmed down, so so important, sealing an old plaster finish is not the answer, rub down first, then seal.

Many many people make mistakes with new plaster and after three/four weeks apply their standard paint.

To late in this case but for the next time, new plaster should be allowed to dry naturally, if plastering is done in very hot weather, keep the room cool, ( close the curtains ), allow as much time as you can to pass before painting, certainty 6 weeks, much longer if you can, one of the reasons for this, is all new plasters skims can shrink and crack so there is no point in say, painting a ceiling, if it has to be done again.

In cold weather never use central heating to dry a room, just have patience, as soon as surface is dry, turn on CH to that room if you have to

The first thinned coat of paint to new plaster is to do with absorption/sizing nothing else, it won't prevent cracking of plaster and the first coat must be allowed to dry thoroughly.

If we have large rooms to do, it is not unusual for us to apply three coats.

Never, ever, ever apply uni-bond/PVA or some such sealant to new plaster----ever.

Standard emulsion to new plaster is never a good idea, there are wall paints for new plaster, it's as easy to apply but much more permeable and that's the secret to an eventual good finish.

All new paint/plaster must be allowed to breath and dry, sometimes up to 6/8 months after the new plaster is applied, before you can use standard emulsions.

So, I think what's happening to your walls is either you have used standard emulsion paint to soon after the skim or you say you have done a lot of drilling or something is interacting with the plaster skim.

It may simply be the old plaster finish has vibrated, moved/cracked and what your seeing is as the old existing plaster starts to break down or crack it is showing through the new plaster skim, this is not unusual, the fact that it hasn't happen to areas you haven't drilled, is fortunate and may never happen.

All houses move, thin plasters skims will be surceptible to this movement.

Have you done any harm,--no,is there something you can do about it,-- may be but you must do it before hot weather.

There are several brands on the market, available almost anywhere, basically it's a very thick paint and it flexes, it is designed for hairline cracks and I mean hairline, can't tell you how many people use the stuff in the hope it will cover cracks.

I would suggest if you go down that route, to rub the affected walls down lightly to get a key,( do do this), then apply, let it dry 5/8/10 days before repainting.

Word of WARNING, if the original existing plaster is breaking down, this work around will work but will not cure the problem for ever if at all.

Re-skiming walls is a standard effective approach for many householders, in most cases it works just fine and resolves lots of issues-----up to a point, however if one is after a blemish free smooth plastered finish forever on existing 70 year old plaster,----- it's not going to happen.
Wow thanks for that.. you really know your stuff. I have 3 more rooms which i hoping to get reskimmed this summer... so your advise has been invaluable.... I'll give them atleast 4+ months to dry this time.

And get some of that flexible paint you mentioned.
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Old 20-03-2007, 21:08
seacam
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Hello Aquazi,

Remember before having walls reskimmed, if you have stripped wall paper. sand/rub down walls with a medium or fine grade sand paper, thoroughly.

Let the new skim dry for as long as posible, then apply paint for new plaster, doesn't come in many shades I'm afraid.

If you can live with the bare skims for a few months, then you can paint with standard emulsion, saves you doing the job twice.

Remember if you go down the standard emulsion route, first coat thin by 15% and let dry thoroughly.
Good luck
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Old 20-03-2007, 22:11
malaikah
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Originally Posted by seacam
Many many people make mistakes with new plaster and after three/four weeks apply their standard paint.

To late in this case but for the next time, new plaster should be allowed to dry naturally, if plastering is done in very hot weather, keep the room cool, ( close the curtains ), allow as much time as you can to pass before painting, certainty 6 weeks, much longer if you can
I had to have a chuckle at this - I had my kitchen and bathroom done up a few months ago under the governments 'Decent Homes' initiative - they came and painted over the new plaster ooh.. about a week or maybe two after it was done!
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Old 23-03-2007, 11:03
aquazi
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Originally Posted by seacam
Hello Aquazi,

Remember before having walls reskimmed, if you have stripped wall paper. sand/rub down walls with a medium or fine grade sand paper, thoroughly.

Let the new skim dry for as long as posible, then apply paint for new plaster, doesn't come in many shades I'm afraid.

If you can live with the bare skims for a few months, then you can paint with standard emulsion, saves you doing the job twice.

Remember if you go down the standard emulsion route, first coat thin by 15% and let dry thoroughly.
Good luck
Just printed that off, and will keep that as a reference. Cheers Seacam, that was a top tip.
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Old 23-03-2007, 12:52
seacam
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Originally Posted by aquazi
Just printed that off, and will keep that as a reference. Cheers Seacam, that was a top tip.
Your Welcolme Aquazi,

Good Luck.
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