Limewash on concrete?

[Keithj]

Wonders never cease, and our builder is nearing completion of the repairs and the extension. The limewashing of the repaired and the new areas is just about complete. Those are all rendered with lime and chalk. The unrepaired areas are mostly concrete.

The trouble is, the fresh limewash shows how much some of the other areas have faded over the years. Something needs to be done. See here:

We have the remainder of the Suffolk pink limewash that was used on the new render - can we use it on the concrete, or should I go to one of those "colour match" places and get some conventional paint? Is Sandtex the way to go if we do?

 

[JoceAndChris]

Oh, I think Sandtex is horrid. Don't put that on your lovely house.

As far as I know, limewash isn't very happy on concrete and won't sit well but having said that I'd be tempted to do a little test patch and see what happens.

I'd give the people at Rose of Jericho a call - they do lovely modern paints too. They might well be able to give you a close match to your pink.

FnB's Middleton Pink could be a close match? It might be available in the Exterior Masonry finish.

If you choose a brand that contains a lot of natural mineral pigments, like the 2 I mentioned ( Womersleys is another range of gorgeous colours), it will be nicer than Sandtex.

Well done for a lot of hard work and coming to the end of a huge project. Xx

 

[worms]

I limewashed my (breeze block and cement rendered) garage to match the house and it worked fine. The house itself is a mix of stone, lime-render and concrete render and the limewash doesn't appear to discriminate between these. I am using plain white, home-made limewash, so the result might be different with the coloured, store-bought variety.

 

[Penners]

Have a read of this - particularly the section headed "Choosing A Suitable Surface": http://www.earthpigments.com/lime/lime-wash.cfm

This and other documents that I've read suggest that limewashing a cement surface is fine, provided it has a suitable key for limewash to cling to.

I have no experience of doing this myself.

 

[Keithj]

Thanks for those - and for a very useful site, Penners!
I said Sandtex only because that's what was in the tin bequeathed to us by the previous owner.

I'll do a small area with limewash and see what happens. I suspect there will also be a part-used tin of matching Dulux masonry paint, because the cheeks of the dormers were resurfaced with cement (they were cement to start with) and are being painted by the builder.

 

[biffvernon]

What you won't be able to tell with a small test area is whether the limewash will fall off after a couple of years - and that seems to depend on the cement surface.

Silica paints such as http://www.beeck.de/english/wir_en/erklbe_fr.html might be best.

 

[Penners]

Interesting website, Biff. It states that "the name BEECK stands for pure mineral lime and silicate based painting systems".

So shouldn't it be called PMLASBPS?

 

[biffvernon]

It's in German

 

[Penners]

Ach, zo...