HELP! Why has my paint done this?!

[GlitteryPenguin]

Have just painted one layer of trade matt emulsion white paint over what looks like orange paint from the previous owners. (Have attached a picture of another orange wall as a sort of “before”!)

We have done the same everywhere else in the house (but over different colours) and it’s gone fine - but this wall has gone streaky and bumpy (you can feel the texture!) we sugar soaped the wall first and used a roller for the paint - exactly the same as everywhere else... so why has this wall done this, and what do I do next?!

Are the bumps like little bubbles?

Was the original paint an oil based paint?

If they are and you've used the same paint in the other areas of the house and they're fine, can I ask if someone shook the can of paint before doing this wall? If they did, it's possibly the cause of this issue.

The only way to fix it is to let it dry, then sand it down with fine sandpaper on a block of wood.

You don't need to scrub hard....just go over the whole wall....then dust it off with a clean, wide paintbrush.

Then vacuum....wear a mask to do the sanding.

Once that's done, ensure the paint has settled fully before using it. Roller slowly.

Not like bubbles at all, it’s just got big thick bits and then run marks and bumps everywhere - really bizarre. Paint has been stored in shed for a week - and was stirred thoroughly with stirrer before beginning...

Don’t know what the original paint was - found it like this!

I wonder if there's damp in there. Is that a wall that connects with the exterior of the property?

I would bet the wall is damp. Is it an external wall?

It’s an internal wall - it backs onto the bathroom but the wall didn’t feel damp prior to painting, no damp showing in the bathroom, and no damp on survey.

We've had this before and it was the paint. It would come out thicker in places and give the lumpy effect. So frustrating and the paint wasn't that cheap either. We had to sand it all down eventually and buy a different paint.

It's possible there's some pipework inside that wall, connected to the bathroom.

You can get a sort of metre to check that.

www.amazon.co.uk/Moisture-Meter-Detector-building-materials/dp/B0036PSX0K?tag=mumsnetforum-21

Partner has just pointed out that the bathroom only backs onto some of the wall - the bit above the door obviously backs onto the hallway and is doing the same.

Also did the crowning and roof with the same paint at the same time and they have come out fine.

Has someone sugar soaped the wall and not washed it off properly? Try washing down a wall, let dry and then paint see if it fixes it. Only way to get rid on the affected wall you've printed is to lightly sand or expect to need 4 coats :(

If it was an oil based paint previously and you’re putting on an emulsion it will just sit there, not sink in. Will it wipe off? If you’ve painted elsewhere and it’s fine, there’s nothing wrong with the paint

was it actual paint? or naked plaster...it does look a bit naked wall ish in the last photo, and that's the sort of effect you can get painting a plaster wall.
ideally you dilute the paint and it means the plaster doesn't suck all the moisture out of the paint leaving odd pigment patches
I'd probably give it another coat and see if it gets worse or not.

Although it looks like plaster, that's what freshly applied, wet plaster would look like. It dries pale pink. Even if it were damp, it wouldn't be that colour.

Definitely not plaster - the other two walls in the room were freshly plastered and looked a very different shade - also I could see brush marks. I’m going to try sanding lightly tomorrow morning as PP have suggested and see if another coat makes a difference

Was the old paint a sheen?

You need to use a sealant undercoat first, it's oil residue from the previous paint. Rub it down and then get some polyfiller polycell problem wall undercoat from b and q, put a coat of that on then try the emulsion

Alternatively, try a coat of zissner BIN, using a cheap or old brush that you're happy to write off, though if it's rubbed down and cleaned thoroughly, a coat of screwfix no nonsense primer undercoat should do the job far more cheaply and less stickily.

Best to test a small area before tackling the whole wall again, though.

Tried the other orange wall in the room - - no streaking but the paint mottled like lots of little spikes. So it wasn’t the wall.

Tried the white wall in the room - same spiky finish.

Sanded them all, cleaned (no sugar soap) and dried. Took all morning!

Tried to roller a primer (Zissner 123) over one of them (new roller) and it looks like it’s doing the same thing - lifting/mottling/spiking rather than going on smooth. (You can see if you zoom in!) Tearing my hair out!

Are you using a roller? Looks like your roller is wet, rather than dry, before use I don't do lots of decorating though, so I may be spouting rubbish.

What type of roller are you using? The photo of the Zinsser BIN primed wall looks as though there's too much paint on the roller.

Get wallpaper. It will be easier in the long run!