Bubbles in paint - despite prepping!

[Wolfgirl]

Hi,
Was wondering if you can help please? Long post sorry, but thought I should give all the relevant detail!

We are decorating our living/dining room for the first time since we moved in 2 years ago. I have never painted before either, but I did a fair bit of research first.

I have just put the first coat of matt emulsion (it's Ecos organic/eco paint if that makes a difference) onto a previously painted wall using roller, and in a few areas there are small but numerous air bubbles appearing.

Before starting to paint we filled and sanded down any holes/cracks (but didn't sand the whole wall). Then brushed off dust then washed all walls with sugar soap, then rinsed and let dry. Rollers and brushes were all new, so really dont think any dust/grime could be the cause. This is what most websites seem to suggest as the cause of bubbles, so need to know what else it can be?

The main wall affected is an interior dividing wall. After finding bubbles, I tried sanding down and doing a skim of polyfilla superfine then re-paining the areas. This seemed to work on most areas but the dividing wall just came up in new blisters slightly higher up. These ones I tried popping with a pin then pressing down, it did seem to work, weirdly! But I'm worried they'll come back when I do the second coat. In one area (on the inside of the dividing archway, so the cross-section of the wall) the old paint came off in quite big rubbery-like strips, so the old paint might be latex paint of some sort I guess?

So I'd like to know what I should do, should I just sand a huge area right down to plaster, and if so, do I need to do the whole wall to get it even-looking, and what should I then do before re-painting? As we were just painting over painted surfaces I don't have any primers/sealers to hand, but can buy if necessary.

Also, I assume they used the same paint in the rest of the house, so if the old paint is the issue, what should I do ideally to stop it happening in future in another room?

Really appreciate your help, husband has no clue and is not as involved in this whole thing as me!

Thanks v much

 

[JohnD]

Did you apply mist coats to filler?

 

[Wolfgirl]

I didn't do a mist coat no, as I thought that was just for bare plaster.
But there was no filler applied originally, where the first set of bubbles appeared. I think all the bubbles are on areas which were just old paint (no filler). The filler was an attempt to get rid of the first lot of bubbles, after sanding them away (then they popped up elsewhere).

Should I do that in general for filler though? Does that mean just a thinned down coat of paint?

Thanks[/i]

 

[joe-90]

Yes JohnD is the daddy. The tiny bubbles are air out of the filler.

The other problem sounds like you are painting over silk paint as that is prone to bubble up (bigger bubbles).

Have a look at Zinsser Gardz or even a cheapo smelly oil undercoat.

 

[Wolfgirl]

Joe-90, I didn't have filler on at least 95% of the areas where bubbles appeared though. Sorry if I was unclear, I was just trying to give detials of the prep work I did; ie I only sanded where I had filled, didn't sand all the walls.

So bubbles were in random areas overlying the old paintwork (but most of the other walls are fine so far). So old paint sounds like it might be silk; didn't know that, or realise it was a issue.

Should I have used that Zinsser sealant everywhere before painting over silk paint then? Is it possible that bubbles will appear later over the entire room do you think? Oh dear!

Thanks for replies so far!

 

[funkyfin2000]

Sounds like you have similar issues to me wolfgirl

Not good...very frustrating everytime painting the room!