Paint on walls bubbling when wet

Hebrews12

We're just decorating our bedroom for the first time since moving into the house.  I was putting some filler on a few areas where the walls had dents etc before we paint and the paint started bubbling up.  When it dried, it settled down again but then when I gently rubbed it down, it all started coming off. I'm worried now that when we start painting, the whole room is going to bubble up.  Has anyone got any advice on what we should do please?  Thanks for reading.

***Edit***  I tested painting on a small area and my fears came true. The paint bubbled up, cracked and peeled off in some areas.  

JGB1955

How long did you leave between filling then (hopefully) sanding and then painting?  I hope your answer is days rather than hours.

Hebrews12

No, it wasn't days.  But I guess I'm more concerned about the effect of any type of moisture getting on the paint and causing it to bubble up.  I've always done my own decorating and this has never happened before.

Hebrews12

I've put an edit and uploaded some photos as I've tested painting a small area at it's a bit of a nightmare. Amy help greatly appreciated. 

baser999

Is there a lining paper on that wall, just plaster or a layer of paint? Maybe you’ll have to scrape off all the bubbly areas of whatever it is.

plumb1_2

Scrap the loose and bubbles flat , then you could use a stabilising solution before painting.
Try a test area first.

Hebrews12

Thanks for your replies.  They're much appreciated.  There's no lining paper and it's paint rather than plaster.  I'm thinking  might need to go round the room and spray a fine layer of water everywhere and then scrape of where it bubbles up.  2 questions though:

1. Will I then need to use some skimmer to smooth over where I've scraped off?
2. When you say 'Stabilising solution', what sort of thing do you mean?

Thanks again.

plumb1_2

1-yes
2-Zinsser  or makes available 

stuart45

Where there are chunks of missing paint, I usually put a skim of Knauf fill and finish over, and then sand. Even the slightest ridge you can feel will show up when painted.

hollie.weimeraner

This can happen if you are painting matt emulsion over silk emulsion from my experience.

This forum can bw a great help https://www.diynot.com/diy/#google_vignette

JohnB47

I believe that it's down to the type of filler you're using and the depth of fill. I had something similar, on a small area, using that simple powdered filler that you mix with water.

When I used it to fill very shallow areas bigger than, say, 2 square cm, it lifted up when the paint I put over it over it dried. It doesn't have that problem when I use it to fill holes and cracks, where the area is deep but not wide.

It could also be that you're applying the filler on shallow areas that are really dry and the wall is drawing all of the moisture out of the filler before it gets time to set. I always dampen the hole or area before I apply filler.

For your type of job, I've found it best to use a pre mixed fine surface filler. The brand name Toupret is often suggested and I bought a tub of that 'fine surface filler' and used it recently.

It works incredibly well. I use it to fill those shallow areas left when old paint has peeled off. A quick skin over with that filler, then a rub down with fine sandpaper, wipe off with a damp cloth and you're ready to paint. No bubbling or lifting in my experience. I used a set of these with the filler:

https://www.screwfix.com/p/harris-continental-filling-knives-3-piece-set/41601

Do bear in mind that it is for fairly large but very shallow indentations. Sometimes I've had to go over with a second coat to get a level surface.