Cracked paint

[Rupster]

The emulsion I applied on to a wall has cracked.

I know I can solve the problem by applying a basecoat before the emulsion, but would applying a mist coat beforehand also work?

Thanks.

[PigletJohn]

a mist coat is required on bare plaster, it will do nothing on a painted wall.

What was on this cracked wall before you painted it?

[Rupster]

There was paint on the wall before I painted it. I don't know whether that paint was also cracked.

[PigletJohn]

if there was dirt or grease on the wall (this is very common in kitchens) it can make the paint craze, so will wallpaper paste residue. The other common cause is painting matt emulsion onto silk, which is fairly shiny so does not stick well.

Some people put PVA glue on the wall, which is very bad.

A photo might help, with your hand in the pic to show scale.

[IsItMeOr]

pigletjohn please can you say what options there are if you have painted matt emulsion onto silk? I have a feeling we might have done that in one of our rooms where the paint has sort of "split" in patches. That was after a few years.

It is on a chimney breast which we use, so I wondered if it might be heat related?

[Rupster]

The old paint may well have been silk. I noticed the same issue on a wall that I stripped wallpaper from and there may well have been some glue left on the wall.

I can't show you any pictures as I've sorted the issue now using Homebase basecoat paint which worked very well with one coat.

I was just curious as to whether a mist coat would also have worked.

[PigletJohn]

if you want to paint matt onto silk, scuff the shine off. Wet and dry paper, 600 grade, is sold in car accessory shops, it is very fine and is used dipped in water. Sponge off the slurry afterwards and rub with an old towel. Because it is so fine, it does not leave scratches that show through the paint. You fold the pieces in half so you can hold them, and turn them over when rubbed smooth.

[Rupster]

Thanks for the info :-)

[IsItMeOr]

Thanks pigletjohn, very helpful.

Just found some of the 600 grit wet and dry on Amazon, so will give it a try.