My freshly painted walls are cracking. Any suggestions on how to remedy this?

Question

Hi Guys, I wonder if anyone can help?

I've recently bought a house and have come to decorating the living room. It was plastered about 8 years ago and is in fairly good condition in terms of finish. Previously above the dado rail it had been painted, below it was wallpapered.

I have stripped off the wallpaper below and cleaned all that up.

The walls above were also cleaned and showed considerable build up of tobacco.

On the bottom part - which was effectively bare plaster I watered down the dulux white matt emulsion and painted it on. That has gone on fine - and subsequent coats look good.

However above the the dado rail (on the previously painted part) the paint is showing signs of fine cracking (mud cracking).

I'm not sure why this is happening? I didn't water the paint down on the first coat. - perhaps I should of done.

I also wondered if there had been a reaction with the old paint/cleaning product (flash&sugar soap) / or tobaco residue?

Either way I need to know 2 things. Firstly - What is the best way to remedy this situation? sand paint right back? and repaint.

And Secondly - how can I stop this happening when I come to do other rooms with the same paint?

Cheers in advance.

Regards

James

Answer 1

It happens if you have too much water in because when it dries all the water goes obviously, and the paint will contract and shrink as its volume decreases. This causes cracks.

I think it also happens when you try and put the paint on too thick, like trying to do 5 layers at once.

Answer 2

sand the wall lightly, use primer, then paint.  when the paint is drying turn the heat down!!!! when the paint dries too quickly it will crack.  Try to have the temp just below room temp - about 19C