First cockup - plaster cracking and pulling away

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Jofo

Jofo

New Member
Hi all,

Hoping to get a bit of advice to 1) work out what I did wrong 2) how best to fix!

For context, attended a four day course at the BTC up near Croydon (which I can recommend). So now just getting into doing jobs for myself, and for mother in law! So I’m hardly experienced, but have had some practical application under guidance.

I’ve been skimming boards mostly, however the MiL needed a room skimming. I blue gritted the whole room, but found the stuff very hard to get onz. I managed to skim the ceiling, and around beams and things no problem (even though the ceiling was a swirly pattern), and all looked good.

However on Friday I popped round to skim two of the walls; I thought this would be the easier bit. However after the 2nd coat a certain part of the wall cracked and pulled Away badly - I had to take the plaster back, see below:

E6DAFA82-6338-44A4-935E-5BB615E248E4.jpeg


Just wondering what most likely caused this? The bit of the wall in question was in the sun, so I guess it could be it dried out too fast. But I was also wondering if perhaps it could be a problem with the wall. The training course focused on fresh plasterboard; this wall had paint on it (hence the blue grit) which definitely had some vinyl content. Any thoughts on what most likely caused the issue?

Secondly then, I now have a skimmed wall with holes in. In order to rectify, I’m wonddring what the best approach is without hacking the whole wall back? I was thinking a quick coat of bonding and then reskim the wall?

Was quite hard to explain all of that, so please do ask questions - advice very welcome!
 
Looking at what came off there’s white bits in it so I’d guess what you were skimming onto wasn’t properly attached to the wall. Take off as much as you can, pva then skim full wall again. You’ll probably need to block out what you took off with some bonding if it’s deep.
 
You've skimmed over wallpaper haven’t you?
Plaster also looks very thick and like you left too long to second coat
 
1. I see no trace at all of blue grit
2.you did a 4 day course
3.distemper
4.pick up the phone
5.call a proper plasterer would of been cheaper than your course to f**k up peoples houses
 
How well fixed is the plaster on the same wall where the sun wasn't a problem , as lurpak said 1st coat looks like too dry for second
 
To answer the helpful replies (Thankyou for those)

1) didn’t skim over wallpaper - the white bits you can see is the paint, which after scraping back with the trowel came off, but was still on the wall where the plaster blew
2) rest of the wall which was out of the sun has adhered fine and not gone anywhere, which makes me suspect I didn’t go fast enough / should have left it for a different day
3) blue grit really didn’t want to go into the wall and stay there - my experience with other primers is they stick like **** - this stuff just seemed to want to smear around the wall - maybe I should have gone over it again.
4) paint is definitely not distemper, has a vinyl content although I don’t think it’s a full on kitchen and bathroom paint.

Will PVA, fill with bond then skim the wall, and work on thinning out my coats

Re those saying “call a professional” - yes, I could have done that, apart from my MiL couldn’t afford one, so it’s this or it’s not happening, and the rest of the room looks good, and she’s very happy. I’m not going out and charging people for this, the whole lot was done for free, so I don’t think you need to lay into people.
 
Jofo said:
To answer the helpful replies (Thankyou for those)

1) didn’t skim over wallpaper - the white bits you can see is the paint, which after scraping back with the trowel came off, but was still on the wall where the plaster blew
2) rest of the wall which was out of the sun has adhered fine and not gone anywhere, which makes me suspect I didn’t go fast enough / should have left it for a different day
3) blue grit really didn’t want to go into the wall and stay there - my experience with other primers is they stick like **** - this stuff just seemed to want to smear around the wall - maybe I should have gone over it again.
4) paint is definitely not distemper, has a vinyl content although I don’t think it’s a full on kitchen and bathroom paint.

Will PVA, fill with bond then skim the wall, and work on thinning out my coats

Re those saying “call a professional” - yes, I could have done that, apart from my MiL couldn’t afford one, so it’s this or it’s not happening, and the rest of the room looks good, and she’s very happy. I’m not going out and charging people for this, the whole lot was done for free, so I don’t think you need to lay into people.
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No one is laying into you from what I’ve read the “professionals” are answering your specific questions they can only go by what you’ve said and 1 photograph possibly a bit of light hearted banter but that’s the way it is
 
Groove37 said:
No one is laying into you from what I’ve read the “professionals” are answering your specific questions they can only go by what you’ve said and 1 photograph possibly a bit of light hearted banter but that’s the way it is
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Yep greatly appreciate the advice, and appreciate if I want someone to really tell me what’s wrong I’d have to call them out to have a look, will try PVA + bonding + Reskim (and will work on improving by getting the layers thinner)
 
If your able to scrape the paint off with the skim then the paint doesn’t have a good enough bond with the wall. The bits of plaster scraped off is one side white where it has stuck to paint or is it mostly same colour both sides?
 
Jofo said:
To answer the helpful replies (Thankyou for those)

1) didn’t skim over wallpaper - the white bits you can see is the paint, which after scraping back with the trowel came off, but was still on the wall where the plaster blew
2) rest of the wall which was out of the sun has adhered fine and not gone anywhere, which makes me suspect I didn’t go fast enough / should have left it for a different day
3) blue grit really didn’t want to go into the wall and stay there - my experience with other primers is they stick like **** - this stuff just seemed to want to smear around the wall - maybe I should have gone over it again.
4) paint is definitely not distemper, has a vinyl content although I don’t think it’s a full on kitchen and bathroom paint.

Will PVA, fill with bond then skim the wall, and work on thinning out my coats

Re those saying “call a professional” - yes, I could have done that, apart from my MiL couldn’t afford one, so it’s this or it’s not happening, and the rest of the room looks good, and she’s very happy. I’m not going out and charging people for this, the whole lot was done for free, so I don’t think you need to lay into people.
Click to expand...
6. Nothing is free
 
stuart23 said:
If your able to scrape the paint off with the skim then the paint doesn’t have a good enough bond with the wall. The bits of plaster scraped off is one side white where it has stuck to paint or is it mostly same colour both sides?
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Mostly the plaster came off the paint - I then scraped it back hard. When prepping the walI I suspect I did a bad job with the primer on that portion. Beforehand the paint seemed very solid (I tried scraping it off to see what the adhesion was).

Will try scoring the wall and doing a better job with the primer in future. Might try a primer without the aggregate in it (if I can find one) might be easier to apply thicker.
 
Don’t score the wall, gives moisture a chance to get in behind the paint. I’ve never bought into this blue grit, pva and skim is fine for 99% of jobs and costs a lot less.
 
To score or not to score that is the question , each to their own
stuart23 said:
Don’t score the wall, gives moisture a chance to get in behind the paint. I’ve never bought into this blue grit, pva and skim is fine for 99% of jobs and costs a lot less.
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Totally agree with PVA comment , but to be fair , I have never used grit ( the price puts me off as well) , if the surface is scored when first coat of PVA it will bubble and show not to use this approach , but I'd rather find out before I've spent time plastering and like the extra grab
 
Havagojo said:
To score or not to score that is the question , each to their own

Totally agree with PVA comment , but to be fair , I have never used grit ( the price puts me off as well) , if the surface is scored when first coat of PVA it will bubble and show not to use this approach , but I'd rather find out before I've spent time plastering and like the extra grab
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Alternatively you could have created a problem by scoring it. Not saying your right or wrong.
 
paulf said:
Alternatively you could have created a problem by scoring it. Not saying your right or wrong.
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That's quite a fair comment Paul , don't usually get that from you:) , I posted about myself double skimming such surfaces , not practical for most people , and understand most people can't comprehend such an approach. Dodgy surfaces that might cause bubbling and delamination , if it's practical I PVA and wipe with a decent coat of MF and move on to other walls , keep an eye on it and trowel only once , its then treated as a fresh overskim when dry . this gives an even suction and less likelihood of wasting 2 or three coats of time trowelling with the moisture standing more chance of causing bubbling which on trowelling up spreads the delamination
 
Havagojo said:
That's quite a fair comment Paul , don't usually get that from you:) , I posted about myself double skimming such surfaces , not practical for most people , and understand most people can't comprehend such an approach. Dodgy surfaces that might cause bubbling and delamination , if it's practical I PVA and wipe with a decent coat of MF and move on to other walls , keep an eye on it and trowel only once , its then treated as a fresh overskim when dry . this gives an even suction and less likelihood of wasting 2 or three coats of time trowelling with the moisture standing more chance of causing bubbling which on trowelling up spreads the delamination
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With re skims over paint or artex you've no idea if its been done properly so problems can and do happen. One thing i would say though is never score artex it'll just allow moisture to get past the paint coat and re activate the artex i.e. it turns soft and mushy.
 
paulf said:
With re skims over paint or artex you've no idea if its been done properly so problems can and do happen. One thing i would say though is never score artex it'll just allow moisture to get past the paint coat and re activate the artex i.e. it turns soft and mushy.
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No i don't score artex only the walls that have those types of paint that the PVA just skins over the surface , kitchens is quite common , you may have multiple surface absorption ( untreated below removed units, removed splash back tiles and painted above) .the double skim approach idea is to not waste time on such and the inconsistent drying areas on trowelling up .
 
I got some Bostik plasterers stabilising solution £30 wickes. Applied it on Friday so be skimming tomorrow on it. Will see how I get on. Thistle bond it £60 sheet in b&q an you have to mix the stuff up, bostik was ready to go. Might not be great though. See what happens
 
choppa said:
1. I see no trace at all of blue grit
2.you did a 4 day course
3.distemper
4.pick up the phone
5.call a proper plasterer would of been cheaper than your course to f**k up peoples houses
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I agree with this. The other parts are a mess too. Not finished to a standard at all
 
Cheer up jofo , look at it this way , you learn more from mistakes , so get them out the way , overskim takes experience , nobody gets perfect results from the off and in 25 years time you will still get caught out occasionally
 
Overskimmed in my house 30 years ago. Doing a bit of renovation, noticed a lickle crack, weeny tiddly bit. “Get it of” thinks I.............about 4m2 in seconds.....
..pffft.
It can happen to any of us.
Btw I agrees that you went over distemper. Lesson learnt. Good luck.
 
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