Filler changing shape when painted or primed

[User1234567890]

I prepped my walls, lovely and flat, but made the mistake of using easifill, so having read about it flashing, I did some reading and used Gardz as there was quite a lot of filler, but it was most definitely flat visibly, and to the touch. When the Gardz dried, the filler had changed shape, it looked like it had risen and changed shape and standing proud of the walls, so the previously flat walls were now lumpy and rock hard. Feathered edges had seemingly disappeared, and all that was left were edges and bumps, like a 3d map. It was as if the filler had completely disappeared in places. That was disaster number 1.

Disaster number 2. I did lots of googling to see what went wrong, but couldn’t find anything regarding the filler changing shape, but did find lots about easifill flashing and quite a lot of people saying to use Toupret interior powder instead. Some bought a 2kg box of the Toupret and got to work. 2 days later, it was all prepped again and looked even better than before, and instead of sealing, I bought some Leyland trade acrylic primer undercoat, which also had lots of positive reviews and people saying how great it was, so went ahead and did a couple of coats. As the second coat was going on, I noticed there were small bubbles appearing in places and on closer inspection, the filler had swollen and changed shape again, just like before. I let it dry and sure enough, it was all weird and misshapen. Wasn’t sure which way to go next, so let it dry for a couple of days and attempted to sand back again. I noticed right away that where it had swollen, it was really hard to sand and rock hard, so ended up cutting it out and refilling with Toupret again.

Disaster number 3. The more I looked, the more raised areas I found that needed repairing, so I did just that, and sanded flat, and then spot primed with the Leyland acrylic. Left it overnight and woke up to the same again, raised super hard, impossible to sand lumpage. I started chipping it off and was going to fill, but decided to get help first.

Not sure where to go from here, I’ve had many decorating disasters over the years, but always been able to fix somehow, but I’m running out of ideas, other than Zinsser bullseye or BIN?

If anyone can help me, it would be very much appreciated, cheers

 

[Chivas69]

Do you have any pictures? I was just about to recomend the Leyland primer which I always use over any filling I do but it seems in this instance something far more strange is going on.

 

[Wayners]

Fill with toupret but damp sponge around edges of the filler as you go. Helps blend in and sanding is easier at the filler edge. I think you might have a step with a difference in levels where filler meets wall. Maybe?
120 grade sand but filled edges won't need much sanding where you damp sponged.
Spot prime with your acrylic primer undercoat.
Then paint.

Toupret doesn't swell or change so I'm puzzled?
One problem you maybe having is the filled areas showing especially with critical light. Put a light up against wall creating critical light as you fill. You may see the problem with that. Can make a wall look terrible shining a light across but only way to see what's going on
Sometimes better to put a skim over entire wall with a wall smoother.
Then sand all the wall.
Prime all the wall.
Yeah easyfill can be a problem filling old walls so I stopped using years ago. It's more for plasterboard jointing.

Need pictures plus information regarding how the light is hitting wall. What's wall surfaces like

 

[User1234567890]

Thanks very much for the replies.

@Chivas69 Thanks, I took some but they didn't show much as the light was poor, apart from the one I'll add below this, and since posting this, I sanded it all back again, but will do some as I go if any changes again today. It was taken after I did the walls with Gards, but you can see the slightly raised outline of the filler that wasn't there before.

@Wayners Thanks, I've been using a really bright LED torch when I'm sanding and when I'm filling, so I'm definitely sure that the surfaces are flat before priming/sealing. Honestly, I spent ages doing it both times and it was perfect.

So, regarding the Toupret not swelling or changing, I was able to recreate this each time, albeit unintentionally. Aside from the filler standing proud slightly, what seems to happen is, the areas where the filler is feathered out the thinnest, that seems to disappear completely when painted or sealed which in turn makes the areas that are standing proud seem more proud than they actually are as the surrounding filler isn't there any more, or has changed. I honestly can't explain it and it has done it with Gardz and leyland Acrylic primer. I have tried spot priming with both Gardz and Leyland at different points and both cause the problems I mention above. But where I spot primed with the Leyland, the filler becomes rock hard and is very difficult to sand, it kind of goes hard/shiny and then starts to chip off as I'm sanding. Even with fine 240 grit.

About skimming the wall. Using the Easiifill, I had fixed so much of one particular wall, it was almost completely covered in it, but when I used Gardz, the major has disappeared and all that was left were the larger, deeper areas standing proud, like you see in the photo. To be honest, the photo shows some of the lesser affected areas, see of it was really bad and lumpy, but what you can see in the photo, is that there appears to now be islands of filler, where before priming, it was all one mass with much thinner layers between the deeper areas.

Regarding the Leyland. I was a bit reluctant to use any more, as it creates small bubbles in the coat below as soon as it gets wet, and then some of them dry like bubbles, which means sanding back and filling again, and that's been the theme for me recently...sand/fill/sand and then there's the thing where it goes rock hard when in contact with the filler?

I was starting to think there was something bad in the walls as I had this room skimmed a few years back and the plasterer abandoned the job as there were large, fist-sized bubbles appearing in the skim, he was popping them with the corner of his trowel and then flattening them, but they were coming back. When he'd gone, I dug out the bubbles and fillered them in and it was fine when painting that time as I remember. During this renovation, I made a stud wall across an alcove for a little WFH office for the Mrs and that wall is completely unaffected by all this, which makes me think that there is something dodgy in the old walls. It's a 1950s ex council house.

Anyway, before you had replied, I found an unopened tin of peelstop, so I decided to do an experiment on one wall, I scraped back the paint and filler to the plaster in the worst affected areas and rollered the entire wall with it. No changes to the remaining filler that time, which is promising, so I will use that wall as guinnea pig today and report back.

 

[Chivas69]

If the paint underneath the new paint is bubbling then there will be a problem with that original paint sticking to the wall/bare plaster. In most cases it will bubble up when new paint is put on but then go back down again once dry. It could be originally there was grease spots on the wall or fizzy pop or even just slap happy pva from the plasterer.
If they are all fairly small areas where the filler looks proud I would bang them in with a hammer so they're below the wall surface area and refill with basic pollyfilla or equivalent. Just basic powder filler. Once dry, sand (should be easy and take seconds per hole) and then just put the leyland primer on the new filler (not the whole wall).