Deep crack filler
Discussion
bmw645 said:
I have a near 2 inch crack in the plasterboard that I need to sort. I was thinking of expanding foam but that's quite messy. If I fill it with polyfiller completely it will just crack. Any ideas please
That is a bit more than a "crack", I would be getting someone in to find out if there is a bigger issue at play.Agreed. If that has appeared, rather than always been that way, find out why.
Anyway, on stuff like this I would cut a piece or pieces of plasterboard shaped to fill the void (use tracing paper to get the design). Then use little wooden "stitches" in thin ply across the back of the crack (preferably screwed in from the front) to glue it to. Them skim over with filler amd sand to seamless finish.
If the surface is horribly uneven, the expanding foam/wood fillet with deep filler options others have suggested are probably going to get you a smoother outcome, but will be messier and likely need more cycles of filling and sanding.
Anyway, on stuff like this I would cut a piece or pieces of plasterboard shaped to fill the void (use tracing paper to get the design). Then use little wooden "stitches" in thin ply across the back of the crack (preferably screwed in from the front) to glue it to. Them skim over with filler amd sand to seamless finish.
If the surface is horribly uneven, the expanding foam/wood fillet with deep filler options others have suggested are probably going to get you a smoother outcome, but will be messier and likely need more cycles of filling and sanding.
It looks like 22mm eps insulated plasterboard, so I’m assuming it’s an external wall. Ideally you’d want to clean up the edges of the hole and use the same to fill the gap, set it back from the face a few mm then finish with Polyfilla or similar. Just shoving gobs of plaster/filler in there may lead to a cold spot and condensation; you’d have to buy an 8x4 sheet though
Polyfilla over expanding foam may work, never tried it and would be a bit messy!
What happened to cause the problem btw?
Polyfilla over expanding foam may work, never tried it and would be a bit messy!
What happened to cause the problem btw?
Definitely find out what caused the "crack".
Is that expanded polystyrene in the crack? Also some dot and dab spots.
Do you know the history of that wall, work done etc? Pro builder or diy?
If it's an outside wall then what does the exterior wall face look like?
If no big problem is found ( just a bodged job) then get some matching plasterboard, cut a section slightly larger than the crack, use it as a template to cut a section of the plasterboard round the crack, fit your template patch and finish with decent filler. Yes, you'll end up buying a sheet of new board but will have some spare for the future. If lucky you might be able to get suitable off cuts instead.
Is that expanded polystyrene in the crack? Also some dot and dab spots.
Do you know the history of that wall, work done etc? Pro builder or diy?
If it's an outside wall then what does the exterior wall face look like?
If no big problem is found ( just a bodged job) then get some matching plasterboard, cut a section slightly larger than the crack, use it as a template to cut a section of the plasterboard round the crack, fit your template patch and finish with decent filler. Yes, you'll end up buying a sheet of new board but will have some spare for the future. If lucky you might be able to get suitable off cuts instead.
Definitely find out what caused the "crack".
Is that expanded polystyrene in the crack? Also some dot and dab spots.
Do you know the history of that wall, work done etc? Pro builder or diy?
If it's an outside wall then what does the exterior wall face look like?
If no big problem is found ( just a bodged job) then get some matching plasterboard, cut a section slightly larger than the crack, use it as a template to cut a section of the plasterboard round the crack, fit your template patch and finish with decent filler. Yes, you'll end up buying a sheet of new board but will have some spare for the future. If lucky you might be able to get suitable off cuts instead.
Is that expanded polystyrene in the crack? Also some dot and dab spots.
Do you know the history of that wall, work done etc? Pro builder or diy?
If it's an outside wall then what does the exterior wall face look like?
If no big problem is found ( just a bodged job) then get some matching plasterboard, cut a section slightly larger than the crack, use it as a template to cut a section of the plasterboard round the crack, fit your template patch and finish with decent filler. Yes, you'll end up buying a sheet of new board but will have some spare for the future. If lucky you might be able to get suitable off cuts instead.
Foam and filler is definitely an option but it will crack at the edges eventually.
If it's somewhere visually prominent then I would just use enough foam to fill the void space to the back of the plaster board and then use actual plaster to fill and then finish with something like Toupret finishing filler.
The problem after that will be the painting as you will have sanded it beautifully smooth and the rest of the wall will have roller stipple so you need to give it a fair few undercoats with a mini roller to replicate that stippling.
If it's somewhere visually prominent then I would just use enough foam to fill the void space to the back of the plaster board and then use actual plaster to fill and then finish with something like Toupret finishing filler.
The problem after that will be the painting as you will have sanded it beautifully smooth and the rest of the wall will have roller stipple so you need to give it a fair few undercoats with a mini roller to replicate that stippling.
I'd probably fill that with offcuts of plasterboard, maybe with some foam behind.
Finish with finishing plaster, then 'easyfill' as needed.
Proper job might be to cut away the face either side and scrim tape to hold the join together.
The issue might be whether the plasterboard either side is in the same plane, if not then you need to decide how to deal with that. Maybe skim to blend one into the other? A change of angle will notice in some light and if it's not constant all the way up it will look a bit 'cottage', which is OK in a cottage, not so much in a modern house.
Finish with finishing plaster, then 'easyfill' as needed.
Proper job might be to cut away the face either side and scrim tape to hold the join together.
The issue might be whether the plasterboard either side is in the same plane, if not then you need to decide how to deal with that. Maybe skim to blend one into the other? A change of angle will notice in some light and if it's not constant all the way up it will look a bit 'cottage', which is OK in a cottage, not so much in a modern house.
I would Pva the gap, fill with bonding, scrim over joints then easifil over the top. The problem is it’s such a small gap you’ll have 95% left over of everything.
You could use this, it does exactly what you need:
https://www.screwfix.com/p/no-nonsense-joint-fille...
You could use this, it does exactly what you need:
https://www.screwfix.com/p/no-nonsense-joint-fille...
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