What have we done wrong with this paint??

[Bumblebee413]

All help very much appreciated- thought we'd done everything right!!

We're trying to paint a mountain mural in our nursery with straight lines, so have used frogtape- extra gentle for freshly painted walls. Hence the multiple cours in the photo.

The wall was freshly skimmed, left for 8 weeks to dry, sugar soaped, left to dry and then given 2 layers of undercoat before we put the colours on. When I removed the first pieces of tape, a few bits of paint came off, so I sandpapered the edges so that the wall was smooth, before repainting. It then bubbled along the edges and started to peel away front the wall and I don't know how to fix it.

Our baby is due so soon and we've tried to do it all right and I'm so frustrated! Another area has cracked for no apparent reason (grey photo) and I don't know why that's happened or how to fix it either. Please send help!! Or write it, either is good! X

The paint is not adhering to wall. There is resistance as it is not primed. What paint is it? I think the undercoat did not take properly.

When you say undercoat what is it that you used? We had to use quite diluted paint for two layers to then be able to put standard Matt paint on it, we d tried silk paint but that apparently doesn't do well with new plaster

The cracking looks like the paint was applied too thickly.

The peeling is because your paint hasn't adhered to the plaster. Did you do a mist coat?

Needs primer on the plasterwork
Had it used the be called size/sizing?

No - not sizing. That's for wallpaper sorry

If it was fresh plaster it needed a mist coat first- emulsion diluted with water.

Thank you for your replies. We went straight for a paint that said it was really good for fresh plaster. Do we need to strip the whole room?

I don't know if this will help but take your frog tape off as soon as you've finished painting. Don't wait for the paint to dry

You should have done a really watered down paint coat x2 on the plaster.

Not sure what the solution is now though- sorry that’s not helpful.

@pigletjohn he might be able to help?

I've never heard of using sugar soap on new plaster, could this be forming a barrier so your paint's not adhering to the plaster ?

On new, I've only ever mist-coated, (very dilute paint to seal the plaster) then painted.

Sugar soap is liquid, unfortunately the wall has likely absorbed that

New plaster needs to be properly sealed
Frog tape should be removed when paint is still wet

Sugar soaping was the mistake, that'll have been absorbed into the plaster and left it full of detergent. Painting over soap is not going to work...

I have no idea how you can fix that though, now you've painted over it.

Assuming as others have suggested that the sugar soaping was the problem, not sure why you were advised to do that with brand new plaster. If you don't have time/money/expertise to reskim it, you could hang lining paper and paint that.

If it's a sugar soap residue preventing the paint from adhering, you could try lightly sanding all the walls to remove this and then try starting from scratch with a mist coat etc.

We’ve just painted a freshly plastered room - mist coat then tow top coats. Delicate yellow frog tape then ruined the edging when we were finishing the skirting boards (several weeks after walls had finished). I can only say it’s too strong even after leaving things to dry forever. It looks like you need to strip back and start again. I would always mist coat regardless of what the paint says.

you used a paint for fresh plaster, you say, as undercoat?

A non-vinyl matt emulsion, was it?

Did you dilute it with water?

It's possible to correct patches of peeled paint using a fine-surface filler, pressed very hard with a metal filling knife, so thin that you can see through it. Scrape off the excess round the edges before it sets. When fully hard, wipe it lightly with extra-fine sandpaper, holding it against the wall but not actually pressing, and dust off. When you repaint it, draw a faint line with chalk, and paint up to it. You can sponge or brush it away after the paint has dried for a week or more.

You may have to cut down on the gin beforehand to reduce shaking hands.

if you want to touch in edges and borders, I don't usually use tape (yes it can pull the paint off once hard) but you can use a fine, soft brush. Steady your hand with a padded stick held against the wall. Signwriters use them. I don't know if there is a proper name.

When you do this against a wall-ceiling arris, or a skirting, you can follow the line, and wipe off any excess with a damp sponge. nobody except you will notice.

Steady your hand with a padded stick held against the wall. Signwriters use them. I don't know if there is a proper name

It's called a Mahl Stick, you can buy one or make your own.