Limewash over claypaint over cement/paint?

[noj]

I was wondering if anyone has tried limewashing over claypaint?

Since claypaint goes on over pretty much everything and is porous I was hoping it could provide a decent key for limewash in a low traffic area?

I've got one (internal) plinth wall that's very securely rendered in cement and largely covered in various paints - all now seems sound, dry and non flaking and removing the stuff would be pretty destructive. This whole wall has been recently rebuilt (in the last 30 years or so), had a new sole plate on top of it at that point but is definitely lacking in the ability to provide any suction.

The cement was encouraged to fall off all the other plinths that had had been pretty mashed about with the usual injected dpc, cement, gypsum and bitumen layers and they're now lime plastered and glowing with white limewash - I'd love this remaining wall to have the same finish and have both spare claypaint and limewash to hand, but it'd be great to know if this is a bad idea before adding two coats of the first and 4 or five of the latter...

Thanks

 

[Zebra]

If you have the required materials, why not try a bit and see?

 

[88v8]

The limewash will adhere to the clay, although of course that has no 'depth' so the limewash won't be able to sink in very much, and so may have even less durability than usual.
Question is, the adhesion of the clay paint to the underlayer; I'd ask the manufacturers.

Ivor

 

[noj]

I'll give it a go I guess.

The claypaint is supposed to cover a multitude of sins (particularly vinyl type emulsion without requiring any sort of pre-treatment) - I've only tried it over lime plaster (new and old), a bit of gypsum and some wood where it's gone on everything uniformly and certainly appears to be something that would not be prone to flaking or bubbling.

I may well claypaint now and then wait until we're past woodburner weather though for there to be more humidity in the air for the limewashing coats.

It could be a perfect cosmetic solution (or a subsequent mess of flakes and dusting)

 

[noj]

It sort of works...

Claypaint sticks really well to the mix of cement and paints. Limewash sticks fairly well to the claypaint - three thin coats so far

However I think that since there's not really any depth of porous material the claypaint it doesn't hold enough moisture to allow the limewash to carbonate very much before it's dried out completely and so it ends up dusting quite a bit if rubbed. Works a bit better when covered with damp dust sheets for 24 hours after applying (which I did with the last coat) so may get better after a couple more.

Not sure if it's better to simply add additional coats over what's there and hope it consolidates, or to give it all a good brush/hoover between coats?

Since it's just a plinth that's chiefly behind a sideboard and in a very low traffic area it's not that critical that it's completely dust free, it's really the colour/texture match to the other walls I'm after.

 

[xanthe]

How about a Farrow & Ball Casein Distemper? Right look and loads of colours, breathable and not so dusty.

 

[noj]

It worked!

Just needed a bit of time in a humid environment to kick off the carbonation. An extra three coats, each left for 48 hours covered with damp dust sheets before the next and it's now a non-dusting gleaming white limewash matching all the others in the room.