Hi, I am new to the group so this question may have been covered. We have calcareous sandstone walls which shed sand constantly. Is there any treatment that can prevent this from happening while allowing the walls to breathe? I have read that a mixture of Epsom salt and water can be applied, but do not know if this works.
I'm not a professional, but have renovated a variety of stone properties in the UK and now working on our place here in France.
First question is whether the wall is inside or outside?
Inside I've used two different approaches in the UK. Standard stabilising solution worked well on sandstone. I sprayed it, but it goes on with a brush (but messy.) Alternative was water based matt varnish diluted 50/50. Haven't used it on sandstone (though I've known others that have) but it worked fine on a lime mortar pointed limestone wall. Both darkened the stone slightly but stopped the dusting. Both appear to retain a reasonable level of breathability.
I've used Thompsons water seal on exterior sandstone. We did want to reduce the amount of water the wall soaked up (very exposed wall.) But there's no suggestion it's breathable! No idea if the stabilising solution or varnish options will work outside. Don't see why not.
Usual trick is, if possible, to experiment in some unobtrusive corner!
Thanks for the feedback. The dusting problem is on the inside of the house. Can you tell me what is a standard stabilizing solution?
If you Google it you should get plenty showing up.
I've checked what I used last: http://www.sealantsandtoolsdirect.co.uk/surface_treatments/everbuild_406_stabilising_solution_5_litre_stab5_P23370.html?gclid=CLKuruGOkc8CFUMo0wodbtsLpQ
Having reread the blurb I can see it says it's good for inside or out.
If you order through Amazon UK they'll deliver in France:
Same product is on Amazon FR but at incomprehensibly horrendous prices.
I think it's called Fixateur in France, if I've got that right you can get it at Bricodepot
But, as usual with painting products, it's a lot more expensive than the UK version!
Thanks. After answering I found the Everbuild 406. I will test it out to see the impact.