Newly Plastered wall is cracking when I paint it, help!

[00db]

I have finished plastering some internal walls and have waited a couple of days before painting. The plaster looks dry all over..

I have just put some emulsion on to the first wall and its started to crack, I can actually hear it cracking when painting! Am I painting it too soon?

When plastering this first wall I ran out of time and had to leave the 1st coat of finishing coat to dry overnight before applying the second coat the next day. could it be this? I dont want to try the same on another wall in case this cracks too..

 

[Richard C]

It sounds as if the second coat is delaminating from the first, did you PVA the wall again before applying the second coat? If you leave overnight, you’re effectively starting over again. If you also over towelled the first coat leaving a polished surface, the second won’t key properly even with PVA; next time put the second coat straight over the first.

I would have left it a few more days but a skim will dry out pretty quickly; if its finish over base then it definitely needs a lot longer. Did you thin the paint down for the first couple of coats?

 

[noseall]

I have just put some emulsion on to the first wall and its started to crack, I can actually hear it cracking when painting! Am I painting it too soon?

this scenario is not unusual. i have had this problem too.

did you trowel/polish the plaster a little too much? i think this can lead to 'stressing' the skim coat resulting in an over compressed surface that is under tension - apply the paint and snap!

the smallest bit of expansion cracks the surface. probably.

 

[Richard C]

I have just put some emulsion on to the first wall and its started to crack, I can actually hear it cracking when painting! Am I painting it too soon?

this scenario is not unusual. i have had this problem too.

did you trowel/polish the plaster a little too much? i think this can lead to 'stressing' the skim coat resulting in an over compressed surface that is under tension - apply the paint and snap!

the smallest bit of expansion cracks the surface. probably.

& there you have a most impressive, technical version from noseall

 

[00db]

I decided to suck it and see with the rest of the walls, these all painted ok. I think the problem with this wall was due to the layers of skim coat. I must have polished the 1st coat too much. I PVA'd it before applying the second but maybe there wasn't enough of a key.

Luckily the rest of the walls are ok, and the cracked bit is going behind an integrated fridge so won't be seen!

 

[JohnD]

You put PVA on a wall before painting it?



ask in the Painting and Decorating forum...

//www.diynot.com/forums/viewforum.php?f=12

 

[Richard C]

You put PVA on a wall before painting it?



ask in the Painting and Decorating forum...

//www.diynot.com/forums/viewforum.php?f=12[/QUOTE]
I think he means between the first & second skim coats!

 

[noseall]

& there you have a most impressive, technical version from noseall