Cleaning old stonework

[Curquhart83]

what is the best way to clean up old stonework?

The building in question is a 200 year old stone house, currently rendered in dry dash which is mostly boss

I plan to remove the roughcast and repoint the stonework but the stonework beneath is in a bit of a mess.... Cement residue from the roughcast, patches of old lime wash etc

To my mind needle gunning would be a very laborious task due to the size of the house and I'm not keen on the idea of pressure jetting with water as worried about water ingress

Any other ideas??

 

[theprinceofdarkness]

Sand blasting would do it. Its a beast of a job, 4000 PSI compressor, bags and bags of grit, full protective clothing and masks. . . You can use acid to remove cement stains from stones, beware it could dissolve the stone as well, though not likely.
Frank

 

[loply]

Depending on the size you might be able to use whire wheel on a angle grinder instead of a sandblaster. You can clean just about anything up with a decent one of those. This won't be as quick as sandblasting though.

I would be nervous about using a need gun on old stone, in my experience those things can leave a pretty distinct 'needled' finish. I would do a test patch before doing the whole wall!

 

[stuart45]

If you live on the coast in Angus the Roughcast was put on for a reason and you might have penetrating damp problems if you remove it.