Cracks between plasterboards

[Adam_notVeryHandy]

Hi,
There are lots of cracks in on the walls of my flat where two plasterboards meet. The building isn’t settling because it’s 8 years old now but I think the walls still move ever so slightly especially from summer to winter when I turn the heating on. I tried fixing one by scrapping it out and filling with common polly-filler but the crack reappeared. Does anyone know a better way? Perhaps something flexible that can handle slight movements? I’d like a longer lasting fix if possible. Cheers!

This is an example of a bigger crack:

This is one which I tried to fill but it reappeared:

 

[KenGMac]

Adam_notVeryHandy, good evening.

OK Sorry but no actual answer from me???

BUT???

If you use the search box on the upper right hand side of this post and type in "Plasterboard cracks" there are many, many previous posts on this subject.

Ken

 

[Adam_notVeryHandy]

I did a search but didn't find a good solution.

 

[KenGMac]

Have you considered lining paper?

Yes there are loads and loads of Plasterboard crack topics many different possible materials to use?

Problem is that the plasterboard in your home will be fixed to timber which moves dependent on the season, combined with the [possible] lack of a correctly filled joint, the most common causation being a lack of a [simple] scrim mesh that in effect reinforces what is known as a well Known very weak area of this form of intenral finish.

Ken.

 

[Adam_notVeryHandy]

No I haven't heard of lining paper. It looks similar to wallpaper when I see it on the youtube videos. I'm not really keen on covering the whole wall as it's a big job, but if I use a narrow strip, I'm not sure how to make the edges not show up.

I have heard of scrim tape but I'm not sure how that would work. How can I the mesh showing up when I put filler over the top?

 

[mattylad]

To make the edges not show up, carefully tear it - do not use scissors or a blade - hand tearing makes the fibres separate more so you can blend them in.

 

[Adam_notVeryHandy]

Ok thanks mattylad. So is the procedure:

Scrape out the crack, pre-fill, stick paper on then put more filler on top?

What sort of putty/filler should I use?

 

[KenGMac]

Adam_notVeryHandy, good evening again.

From the top.

Lining paper is simply an un patterned, un decorated paper simply a plain white paper, it comes in various thicknesses the thicker papers are used to conceal to a greater extent minor defects on a wall.

Scrim can be a variable material, but in its basic form is a hessian lattice that is embedded into the plaster over the plasterboard joints, the Scrim in effect reinforces the plaster to allow for crack movement.

As mattylad above using the thinnest lining you can find it should work, but [there is generally a but] watch your interior lighting, do not place a standard lamp in front of the lining paper on the wall.

Ken.

 

[Adam_notVeryHandy]

Hi Ken,

Thanks you for the explanation about the paper. Could I get some details on how to put it on?

Should I pre-fill the crack before laying on the paper? Do I need to put glue on the paper before sticking it on? Once it sticks on, do I just paint over the top?

 

[KenGMac]

Adam_notVeryHandy, good evening again.

OK gently scrape out the cracks, and fill, then sand, and re-fill, then [surprise surprise] sand again.

Paper the area as described by mattylad above, suggest you have a look at YouTube for papering and how to.

Suggest you do NOT re-fill any areas of the paper you will end up with a "bulge"

Then simply [once dry] paint over the paper and the wall itself

As a recap, lining paper is used to make plaster walls that shall I call it are not totally flat and can have small but a lot of minor imperfections look really quite good once the entire wall or room is papered.

Ken

 

[Adam_notVeryHandy]

Ok thanks Ken. I'll go with the lining paper as you suggested.

One last question, what kind of filler would you suggest? Will standard premixed polly-filler do or something else?

 

[KenGMac]

premixed polly-filler do or something else

As previous posts, and your interrogation of many, many previous posts on the board, there are loads and loads of different opinions as to which filler is best?

I am sorry but I have no first hand knowledge of which filler is best, could be that someone will jump in here and provide some assist?

Ken

 

[Adam_notVeryHandy]

Hey guys,

Could anyone recommend a filler for plasterboard joints?

I can see a plethora of fillers like ready-made, powder, putty, decorators caulk. Which one has the greatest flexibility/resistance to movement?

 

[opps]

I would open the cracks slightly. You need to make sure that you do not cut through any scrim tape though. I use a chisel a couple of mm either side of the crack and push gently until the filler falls out.

Once done, buy a tube of Toupret Fibacyl. Gun it into the crack and remove any excess. It is like decorator's caulk but has tiny fibres in it. Leave it to shrink back (over night) and then fill with Toupret RedLite which is a lightweight filler and allows for a degree of movement.

As a belt and braces approach, I often brush PVA wood glue in to the crack first, wipe away the excess and then let it dry before using the Fibacryl. The RedLite filler doesn't change in colour as it dries so it can be difficult to work out when it is dry. I normally leave it for a few hours and then sand with 180 grit silicone carbide paper. I love the fact that the dust doesn't become statically charged and stick to everything (unlike the powder fillers).

KenGMac is correct that lining paper will mask hairline cracks in most cases.

 

[Adam_notVeryHandy]

Hi opps. Thank you for that detailed description of the process. That's very helpful. It seems like Toupret Fibacyl + Redlite is the way to go.

I just have one more question. I also have a slightly different but similar problem, where I get cracks were the walls meet ceiling. I parts the lining paper is coming undone. Do you think the Toupret Fibacyl + Redlite combo would work in this scenario as well?