Tiny hairline cracks in plaster

[amyboo]

I've just had a lot of re-rendering and skimming work done in the hallway and lounge of my appartment. The plasterers have done a good job, but the main guy told me today that there are some tiny hairline cracks which keep appearing in the plaster. He reackons it's down to the age of the place (1935 building), and says they've tried to get rid of them but they keep appearing. In fairness, you can't really see them unless you look closely, but I'm just wondering if they will cover up with paint? He told me to use flexible paint designed for this type of surface. I've found some Dulux "flexi-paint" which says it will stop cracks appearing (and a similar product by Polyfilla). Is it worth using these or should I just use my normal matt ceiling paint? If I use this paint, should I still water down the first coats? Thanks for any helpful hints.

 

[joe-90]

Don't want to worry you but it sounds to me like the wall wasn't prepped properly (too light on the PVA). This allows the walls to suck out the moisture from the plaster before it sets. It also means that the plaster skim won't be bonded properly and when you get the roller on it it will pull pieces off.

Try some cheap contract emulsion watered down 25% and see what happens.

You shouldn't need special paint for new plasterwork - that's why you had the walls plastered.

 

[Richard C]

Were the cracks there before?

 

[amyboo]

Apparently there were cracks underneath the old paint (which they took off as it was flaking all over the place). It seems to be because of movement in the floor of the upstairs appartment, and their noisy energetic kids who run all over the place.... The plaster's definitely solid, and in any case, the same builders did skimming in a back bedroom (where there's no kids running about upstairs) over a year ago, and that plaster is fine. So, I would be surprised if it was down to incorrect preparation. Should I just use a watered down paint then rather than the special stuff?

 

[Richard C]

I always reinforce hairline cracks with tape prior to skimming. If it looks more serious, I hack off a bit of the base plaster to check if the block/brickwork below; if that’s cracked as well, I remove the plaster 200mm either side, reinforce with stainless steel mesh, apply new base plaster or render & then re-skim. It can add up to a lot of work but it’s the only way your going to stand any chance of preventing them reappearing. My success rate is almost 100% but there is no guarantee they wont reappear & if you’ve still got movement or a bunch of screaming kids running around & jumping up & down upstairs, I don’t think you stand any chance; Try sending your considerate neighbour a bill for the rectification work!

 

[joe-90]

You can't plaster over flaking paint as the only thing holding the plaster up is - flaking paint. My guess is that they haven't got all the old flaking paint off - and now it's coming loose. Plaster doesn't crack without a reason and that reason has nothing to do with kids.

 

[Richard C]

Snap

 

[amyboo]

They definitely got all the flaking paint off - I saw the ceiling before they did the skim!

Kids upstairs are a pain in the rear, and the floor upstairs is a hardwood floor....Surely even if he took the plaster right down, if there's movement in the ceiling from the irritating kids upstairs jumping around like elephants, then the cracks will just reappear anyway? I put my hand up to the ceiling last night when they were running around, and there's definitely slight movement.

Is it worth even trying this flexible paint, or should I just try a normal mist coat and emulsion?

 

[Richard C]

Kids upstairs are a pain in the rear, and the floor upstairs is a hardwood floor....Surely even if he took the plaster right down, if there's movement in the ceiling from the irritating kids upstairs jumping around like elephants, then the cracks will just reappear anyway? I put my hand up to the ceiling last night when they were running around, and there's definitely slight movement.

Is it worth even trying this flexible paint, or should I just try a normal mist coat and emulsion?

I think I already answered that one; your onto a looser there I'm afraid.

You could try flexible paint but I’m sceptical weather it will work; personally, I don’t like the stuff but have no real experience of using it.

 

[amyboo]

OK. Thanks for the comments. I guess I just paint it normally, and then have a "discussion" with the upstairs neighbours about their kids' indoor exercise!

 

[roy c]

You could always put "Blown vinyl" paper on the ceiling!!!

 

[Richard C]

You could always put "Blown vinyl" paper on the ceiling!!!

Or even woodchip

 

[roy c]

You could always put "Blown vinyl" paper on the ceiling!!!

Or even woodchip

Come on Richard, Blown vinyl comes away alot easier than "Wood-Chip" if you ever have to remove it...

 

[amyboo]

You could always put "Blown vinyl" paper on the ceiling!!!

Or even woodchip

We just spent a week stripping woodchip and vinyl wallpaper! It's never going back up anywhere in the house!!

Thanks to Richard C's comments, I got the plasterer to knock out some of the plaster, tape the serious cracks and re-skim. Looking good so far, despite the kids upstairs trampling around last night.