Exposing Stone Internal Walls

[peterd]

I've recently completed an extension/conservatory and would like to retain the natural stone finish of what was the exterior wall of the house (pre-extension).

As you might expect, this wall has been open to the elements during it's life (over 100 years) and would need some treatment.

Simplicitically speaking I'm thinking that I'll have to "wash" the wall down (pressure wash?), re-point locally and then finish. But as always, I'm thinking that it's not that easy.

If anyone has any advice or links, it would be most appreciated.

Advanced Thanks

 

[erusfarley]

Hi, we have a stone house (a bit like cotswold stone) all we did (makes it sounds simple but its not) was chisel off all the bits of plaster, concrete etc.
then wire brush all over to get good surface look/ colour etc,, chisel out and repoint, after about 30 minutes of the mortar being in, we brushed it over with a soft damp paintbrush, wait for it all to dry, give a really good vacuum, then brushed on a watered down pva solution, about 20% pva to 80% water to prevent the dust coming off, worked a treat for our stone, gives no false shine and everyone coments on how good it looks.

I can send pics if you like, email me your address and i can send some over.

 

[Gervase]

Don't use a pressure washer! Most washers, even the cheapo B&Q own brand models, pump out water around 100bar, and that's enough to drive out the originally jointing mortar to a depth that will weaken the wall. I'm afraid it's down to hand tools only, unless you're removing modern cement pointing from extremely straight and regular joints, in which case a diamond or carbide mortar rake on an angle grinder might do the trick.

Wire brushing would be fine with a hard stone like granite, but would be risky with softer materials like sandstone (including Cotswold stone) and slate - better to leave the stone as-is, save for a brush down with a stiff-bristled churn brush and concentrate on the pointing - using lime mortar.

In essense, apart from the pressure washer, it really is that easy, as you suggested in your post. Go for it!