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Can anyone tell me what to buy to do this. I have had a wall pointed then cleaned the stones up with some acid stuff and now want to seal it. Someone mentioned PVA glue mixed with water but I can't remember what quantities - we tried a test of this and it didn't really do anything.

Help!!

I'm not sure but if you want to DIY you could talk to Tracey at Leroy Merlin.

wood glue or pva (uni bond as it would be called in the uk) would be the cheapest solution, watered down 4:1. this will put a fine film over the stone wall. it will help but i'm sure it will never illiminate 100% any dust falling off. its also worth remembering that you need to let the walls breath and sealing the walls totaly could trap moisture and cause the mortar to crumble. sika do a product similar but is very expensive.

I would be very wary of putting a sealant on stone. I am still working on our stone house in Scotland, (admitedly more damp than France), going on 5 years and more to do - in trying to undo previous owners use of cement and modern paints that trapped moisture and destroyed the fabric of the house.

If the house was built of stone using lime mortars then there it should be restored with the same materials so that the walls can breath.

See excerpt from Societyfor the Protection of Ancient Buildings.
Q. Will sealing old buildings help stop rain penetration?
A. No, this is normally disastrous. Old buildings need to ‘breathe’. Whereas modern buildings rely on excluding water with a system of barriers, buildings that pre-date the mid-19th century are usually constructed of absorbent materials that any allow moisture that enters to evaporate back out – the ‘raincoat’ and ‘overcoat’ effects respectively. Attempts to seal old buildings with hard cement pointing and render, tanking, plastic-based paints, colourless water-repellent treatments and spray-on roof foams entrap moisture and are regular causes of deterioration. Ideally, such impervious materials should be removed but this may not be possible without causing further damage. Be wary of written guarantees, which are often loaded with ‘get-out’ clauses and may have no insurance backing. The right approach from your contractor coupled with good workmanship is your best warranty.


My understanding is there is no approved sealant thet works. There are some permeable stone coatings, (expensive), but they fail after about 5 years and have to be reapplied. Each new coat reduces the permeablity so after a while the stone is permanantly sealed. It is an irreversible process.

Limewash is the traditional coating - but if you want to leave the stone fully exposed on the interior you just have to dust it with a feather duster or hoover the walls occasionally.

Our local (very soft porous stone) stone masons use linseed oil diluted in white spirit.

The white spirit evaporates leaving a very fine film.

The newly renovated joints look good, but not new !

Peter

Thanks everyone for this - Peter do you happen to know the quantities he uses and does anyone know where to buy Linseed oil from - is it on the same shelf as the olive oil in the intermarche?!

I asked the guys who were doing the work and they said 1 linseed oil to 5 white spirit. It was applied with a large "brush".

Problem is that these things vary with the sort of stone.


Peter

I guess it is worth visiting a local stone mason and chatting with him ?

That is one source of my info when I had some stone work to do.

Peter

My son tried sealing his stone walls at his cottage in N Norfolk with Unibond,and it certainly did not work terribly well. In many ways it did only exascerbate the problem. Not sure if he used any of the other suggestions mentioned here,but in the end I think he just left the wall to breathe.

My other thought,Steve is that presumably you are talking quite a big area,and,as Dave says, Unibond etc is NOT cheap!

i think everyone has a valid point. however every situation is different, from most peoples experience the underlying problem is damp ,then sealing the walls as we know is not a solution . steves wall , he tells us is an internal wall so moisture penetrating from the weather should'nt be a problem and i dont know if this wall is ground,1st , 2nd or 3rd floor. lets say it is 3rd floor internal then my guess would be the wall isnt damp , it has recently been re-pointed ,then putting a coat of uni-bond over it on one side should have no ill effects . the obvious thing to do steve is to ask the macon who re-pointed the wall , he has seen it and should know the situation , the type of stone and why you are trying to seal it.
if the wall is suffering from damp then dont waste money on re-pointing and sealing get the damp problem solved first.

I have been told to use a stabilising solution. This is the same as you would use on a concrete floor prior to painting it and doesnt stop the wall/floor from nreathing. It is pricey in England and I dont know if its available here or indeed what it is called.