Filling cracks in plaster - ? skim or lining paper

[Sparkysea]

Hi Pistonheads

Please see pictures of inside kitchen wall which was newly built 3 years ago. All is structurally ok but it has had 2.5 years to dry out now and I 'm not sure what to do about the cracks that appeared a few months after drying out when radiators were on.

We used Sika in the mortar mix beneath the plaster to stop damp from the ground and I think the plaster has cracked where the Sika ends i.e. half way up the wall.

Now I just want to address the cracks. I am hoping a reskim would do the job but not sure if cracks would come back? Someone said I would have to put lining paper on wall, which I don't want to do.

If I do skim how is it best to address the cracks first please?

Thanks for your thoughts

[Sparkysea]

[Steve Campbell]

When we had similar around a new fireplace, we just dug out the cracks and scraped them back with an old screwdriver, then used Polyfilla smoothover, sanded and blended in to a flush and smooth finish and painted. That was 4 years ago and you can't see it at all.

[trev540]

Rake out the cracks so you can get a good depth of filler,probably need filling a couple of times,if there is movement it would crack through the paper as well.

[Sparkysea]

Thank you Trev - I'm hoping you mean rake out and fill, sand down and fill again - not fill wait to see if cracks and fill again?

[Paul Drawmer]

Those cracks are quite fine. I'd just use fine surface filler, and it wouldn't need sanding either.

Strike or similar would do it. Very easy to use.

[227bhp]

If you want to go belt n braces then get some plasterboard joint tape, hack enough off the wall to get it in over the crack and then fill over.
This will give you less chance of it cracking again than just filling it.
Alternatively fill and hope....

[alanyork]

New Build ?? Was it sand & cement render then skim, Normal new build is dry line and skim, You say you used silka ?? was that in the render mix , , Is it only the top skim coat whats loose (cracked) or is it hollow all the way back, Anyway I would just rake out and fill , sand & paint.

[hyphen]

If just the cracks and wall otherwise fine, then I would be inclined to not skim- just open up the cracks and fill with Toupret filler .

If skimming, I would open up the cracks, put plasterboard tape and then skim over.

[m3jappa]

Rake the, out as much as possible and then use easy fill. You will need a couple of goes over it but it's significantly better than poly filler and you can achieve a finish which is so good you'll never know where they were.
Be prepared for the hideous white dust though.

[hyphen]

m3jappa said:

Be prepared for the hideous white dust though.

My first time was my last time Mirka Abranet hand sander connected to a vacuum is cheap.

[JonV8V]

As others, scrape out and fill. I tend to use plaster rather than a filler. Never done this myself (most of my work is limited to where I've had to create access to behind a wall for cabling) but a tip with fibre glass is I think to drill a small hole at the end of a crack to stop it spreading. May be pointless on a wall but can't hurt.

Be prepared for a lot of sanding and dust. Paint after with a roller to get the same paint texture that was there before

[Sparkysea]

Thanks for all the feedback everyone, I think I will have a go when I don't need radiators on, as will have to remove them...

The plaster was skimmed to plaster board and behind this was a mortar sika mix on top of breaze blocks...

Just wondering how far you scrape out...? not easy to describe I suppose

[hyphen]

Sparkysea said:

Just wondering how far you scrape out...?

There isn't a standard. You open up the crack till the plaster is solid all around. Taking a bit more out is is better than less.