Lime plaster crack repair

[Zebra]

What do you all reckon to fill it with? I've previously used flexible decorators caulk to good effect, it seems to limewash over OK. The whole room is timber frame and shifts a bit with the seasons, and it's cracking along the lines of the woodwool boards I used as a base for lime plaster. So I reckon it'll always crack again, I just seem to be shifting the crack elsewhere every time I repair it!

 

[Zebra]

 

[Cubist]

Hi Zebra,

I've used Ty Mawr's General Purpose Filler to good effect with similar 'movement' cracks/damage. Very cheap, easy to use and great to shape to meet contours. For wider gaps they also sell a mesh that can be used to support the filler.

Hope this helps.

Cheers,
Cubist

PS I've also used caulking cotton loosely pushed into wider cracks to do the same job a a mesh.

 

[Zebra]

That Ty Mawr general purpose filler is interesting - it's just NHL and small aggregate, I could make something similar, but I hadn't thought to use something that sets as hard as NHL, the plaster would end up softer than the filler as it's putty-based, but thanks for the tip!

 

[Sam W]

I've found the Ty Mawr filler good for big cracks, but it is quite coarse and doesn't work so well in small cracks. They sell a casein filler that is much finer, more like a standard Polyfilla texture. Only drawback I've found is that it flashes through paint pretty badly.

 

[malcolm]

I've got some similar cracks and plan to just use the same lime mix as I originally used. Or maybe a finishing lime plaster mix where the original mix was course.

That won't stop cracks after further movement but I can't think of anything I would be prepared to use that would

 

[a twig]

Presuming you can't be arsed to hack out the joins and apply mesh like what I did? https://www.periodproperty.co.uk/forum/threads/plastering-question.16738/#post-227203
Then yes, one of the filler concoctions from above should help

 

[88v8]

Earthborn casein filler seems to grip pretty well, and is porous/breathable.

What a fag having your lovely plasterwork crack though.

Did you scrim the joins of the boards? If not, I fear a repetition. Perhaps you could paint a design on there that incorporates the crack.

Ivor

 

[Zebra]

Hi all, still not got round to doing anything yet so thanks for suggestions... 88v8 I actually glued the edges of the boards together with gripfill, whether or not that's a good idea.... elsewhere it's worked out fine, but the bedroom being entirely timber frame I guess it's always going to shift a bit so .... I reckon there's always going to be a new crop of cracks, and perhaps, the better I fix them the more new places they'll appear in! As I said, I tried decorator's caulk, I've tried mixing fine lime plaster with a bit of woodfibre fluff as a binder... maybe I could mix all of them together!!

 

[Cubist]

For

I've found the Ty Mawr filler good for big cracks, but it is quite coarse and doesn't work so well in small cracks. They sell a casein filler that is much finer, more like a standard Polyfilla texture. Only drawback I've found is that it flashes through paint pretty badly.

For very fine cracks I've used small amounts of Lime Putty with no other additives. I'm told one can also add finely crushed/milled chalk to bulk the putty out if wanted.

 

[Zebra]

Got around to fixing this today. Two months procrastination, not bad.... Went for malcolm's suggestion and just bunged some more of the same plaster in there as before, with a bit finer sand.

 

[Cubist]

Got around to fixing this today. Two months procrastination, not bad.... Went for malcolm's suggestion and just bunged some more of the same plaster in there as before, with a bit finer sand.

Horses and courses I suppose..... bother, another animal reference.

 

[Zebra]

I think we can bear it.

 

[paulc]

I've tried mixing fine lime plaster with a bit of woodfibre fluff as a binder...

I'll often bung polyester fibres in to a plaster mix. Long (12mm) fibres for base coats, and short (2.2mm) fibres for top coats. Finishing coats, no added fibres.

Plaster and Render Fibre Additive

Render and plaster are particularly susceptible to cracks occurring during the drying process, these cracks can lead to significant problems at a later stage. Adding TDP Plaster and Render Fibres can reduce cracks and shrinkage, it works by holding the moisture in the material whilst it is...

www.tdp.co.uk

 

[noj]

I was thinking of making up a couple of small tubs of filler.

For the fine stuff I'm going to buy a kilo of whiting (similar price delivered to a whole sack without delivery!), for the slightly bigger bits I was thinking of using fine paving sand which I've already got. Then with some putty, probably 1:1 by volume, although open to suggestions, I can mix two tubs and keep sealed pretty much indefinitely until a little is required.

Hoping that having this on hand will reduce the procrastination when I notice a crack appearing.

There's the ten day rule for little jobs - either you do them in the first ten days or you stop seeing them for months, or years...

 

[Zebra]

I like the ten day rule. In fact, my procrastination would have gone on much longer, but I was filling a crack on the chimney, and a trowelful of plaster on the go is a wonderful thing.

 

[tanyatown]

Hello! If you have contantly moving cracks and you're doing works why not consider the the Sarah Beeny trick to stop them going all over the place. I have tried it in Italy, now I have a nice straight hairline crack in the same place that I just ignore now as it opens and shuts with the weather. Before they destroyed everything. I the case I'm referring to I didn't need to use a mesh. The trick is to hard render either side of the movement area, I used a foam as my gap was a good 7 cm. Then over that I used a thin coating of stucco.