Limewash on flint

[Pford75]

Some of you may recall that we are in the process of applying for LBC to remove all the horrible sandtex from our house and then limewash it. Have been browsing the Rose of Jericho website tonight looking at colours (can't decide) and something struck me.

A small section of the building is flint (where a building stood before ours and the wall was 'reused')...whilst sandtex seems to stick only too well to the flint, I wondered if I will have a problem with limewash?? RoJ state that limewash can only be applied to porous surfaces...which flint obviously isn't. I can't leave the flint unpainted, since it would look odd against the rest of the house...nor do I want to render everything. Has anyone here had experience of limewash on flint?

 

[worms]

RoJ state that limewash can only be applied to porous surfaces...which flint obviously isn't.

While that advice sounds right, I have limewashed over Dulux Weathershield without any special preparation and it has held well. Or is Weathershield porous in some way?

 

[Flyfisher]

I wonder if silicate paint would adhere well to flint? It's supposed to be a suitable and much longer-lasting alternative to limewash, albeit more expensive. Perhaps silicate paint the flintwork and then limewash over it for a colour match with the rest of the wall?

Just an amateur rambling though, so you'd need to check with some real experts first.

 

[robgil]

spab says the same thing.

http://www.spab.org.uk/advice/technical-qas/technical-qa-18-limewash/

my gut feeling would be to try it anyway.
you could find out about distemper? or give Mike Wye a call
http://www.mikewye.co.uk/

 

[Pford75]

FF - Any good silicate paint links?

 

[Flyfisher]

This is the one I bookmarked when first starting to read up on silicate paints: http://www.buildingconservation.com/articles/vapour/vapour.htm

http://en.wikipedia.org/wiki/Silicate_mineral_paint is a basic introduction with some links to manufacturers.

Although limewash is relatively cheap, its 3-4 year durability, coupled with the need for scaffolding in our case, makes it a rather expensive proposition. Silicate paint is a lot more expensive (around £100 per 10 litres) but is claimed to last for at least 20 years.

But I've not yet found anyone who has actually used it, so all this is just what I've read.

 

[Pford75]

Have been doing some research on the silicate paints this morning. Am I right in thinking that most of them are 2-part systems? ie. They need to be primed? Speaking to someone from TyMawr, it would seem that the 'primer' sounds very much like a thin render......which rather defeats the point (If I wanted this finish, then I would simply lime render and then limewash).

Perhaps I have misunderstood? :?

 

[chuckey]

I think the problem is with the glass like surface of knapped flint. I would have a go at it providing the lime wash contains linseed oil. This should make the lime wash "sticky" else I reckon the first drop of rain would wash it off.
Frank

 

[Penners]

I don't think I'd risk limewash over flint. It's not a durable finish under the best of conditions, and on flint I don't think it would last any time at all.

I like the idea proposed by Flyfisher. As he says, an expensive paint that lasts a long time is probably going to work out cheaper than limewash, which won't last. This is particularly true where you have the added (considerable) expense of scaffolding.