Decorators Caulk - Good all round crack filler?

[michael]

Does anybody have any experience with ‘decorators caulk’? Thought this might be a good all round option for filling a few hairline cracks indoors and out on numerous surfaces, old lime plaster, old painted stucco render, modern gypsum plaster etc. I understand that it’s very flexible and can also be used outside as long as its painted over.

 

[Gervase]

I wouldn't want to use it outside, but for gaps around door frames, skirtings and the like it's good stuff. Certainly infinitely preferable to silicone.

 

[ilikecobwebs]

Following a total re-wiring of our entire house this summer, we had decorators in to repair all the inevitable damage, and re-paper/paint walls and woodwork. They've used caulk on the skirting-board gaps, doorframes, picture rails and a variety of other little fiddly nooks and crannies. It all looks pretty good so far. (er no, we chickened out of doing the decor ourselves, this time it was just physically far too much work).

 

[biffvernon]

So what exactly is decorators caulk? And what was it before acrylic was invented?

 

[Ian Millington]

So what exactly is decorators caulk?

It is (according to the packaging)

A viscous, thixotropic & water-based dispersion
incorporating magnesium / calcium carbonate fillers,
styrene acrylic co-polymer emulsion, cellulose ether,
in-can preservative and wetting agents.

All I know is that it is pretty good stuff for inside jobs.

 

[biffvernon]

Yes, but more intriguingly,

And what was it before acrylic was invented?

 

[Ian Bond]

I've mostly managed to get away without using caulk, by fitting skirting prior to the final skim of plaster, and being very careful to get a neat join. Ditto with architraves etc.

Where I've fitted picture rails and so on, where the walls dip I've packed out the back of the mouldings with strips of wood to mininise the gap. Then decorators caulk has come in very handy if I'm not skimming the wall to hide the small(er) gaps.

But I've found pure lime putty to be a perfectly good filler for tiny cracks and gaps in the plaster.

Elsewhere in my house, later Victorian alteration have been made to the skirting, and some has half inch gaps at the top. It looks as though they packed out the gaps with odd bits of lath and chucked plaster into the gap, to finish the join.

And perhaps because they didn't have decorators caulk to fall back on, they were more careful with their workmanship? I've since redone some bits of joinery done by professionals. I use the term 'joinery' loosely. More like badly fitting pieces of wood joined together with decorators caulk....

 

[michael]

I would be interested to know why decorators caulk can’t be used outside. I have a couple of hairline cracks in my exterior cement stucco. This stucco is around 125 years old and is cement not lime. The cracks are very fine, not too serious and have been there for many years but the wall in question is on high ground and south facing so it gets direct hot sun in the summer and direct wind and rain in the winter consequently the cracks expand and contract like a squeeze box and none of the standard fillers seem to hold up. The cement stucco has unfortunately been painted with modern weather shield paint by previous owners. The property is quite large and so and I’m not prepared to go to the efforts of removing this. The guys at the local paint store advise me that the caulk will be ok outside as long as it is painted over. I thought it might be worth a shot as none of the other options seem to have the desired flexibility.

 

[Ian Bond]

It *may* work fine Michael - give it a try, it will only be a waste of a pound if it doesn't work.

Caulk has failed on my house exterior where it has been used incorrectly. For example, fitting a 'nosing' to a window cill using nails, and caulking the gap. Or caulking between fixed window lights and the frame. Not by me, again by professionals who will not be coming back.

The wood moves a fair bit, and the caulking doesn't always cope. Also, the paint has cracked along the caulked line, again due to differential movement. With less caulk, in a thin crack you might get away with it.

A pity about the weathershield perhaps, but if its not causing a problem, then what you're proposing sounds OK to me. No point chucking loadsa money away on a non-problem.

 

[bower1]

I always use frame sealant outside, rather then decorators caulk. I have used it as a (lazy) way of filling thin cracks outside, but if the surface is not very textured, it will be visible.

You should paint both caulk and frame sealant as it goes grey quite quickly.

I would not use caulk on internal cracks (except at the edges of walls or around frames) as you cannot sand it.

 

[Cloudscape]

All caulks were not created equal. I was trying to economize a little on my last Victorian house. It was very cracky in corners, especially where the ceiling joined the walls, and around doors and skirtings. I tried the cheaper caulks and found that they harden, shrink and crack. You end up filling cracks in cracks. :shock: I decided the cheaper caulk is extended with something like PVA glue, or that 'No More Nails' stuff. Maybe there's just too much water in it, out of the tube.

Externally, I have used only frame sealant (sparingly, around doors and windows, and some decorative timberwork), and always painted over it. Never had any problems - even ten years down the line.

Now I'm doing the stone/lime thing, and will try more traditional materials.

 

[Gervase]

Papier mache was the filler of choice before caulk, and still has its uses. Caulk is more convenient, though, and is less likely to grow mould!

 

[biffvernon]

Does that imply that the term 'decorator's caulk' was not used before the inventionon the acrylic-based stuff in the tube?

 

[Gervase]

Caulk has been around for ages in many guises (such as teased-out oakum for boats), but perhaps the "decoraters'" prefix was a bit of marketing.

 

[biffvernon]

Ah, but did the marketing prefix only appear with the modern stuff?
What was the medium in the papier maché?