Cleaning stone mullions

[JonnyMercUK]

Ive recently embarked on a project (bigger than the last one!) and the first job before the new windows go in is to clean the stone mullions.

Just wondering what options are out there? I’ve tested with my pressure washer however don’t think it’s going to be strong enough.

I’ve attached a pic, they are just generally mucky from the near by road and trees.

Any suggestions?

 

[Burnerman]

Is there anyone who offers wet grit blasting near you?
It can be quite expensive unless there's a lot to do, but its dramatically effective and done in a flash.
John

 

[JonnyMercUK]

I’ve done a search for sand blasting but nothing has come up trumps.

 

[geraldthehamster]

Struggling to see any mullions ...

 

[Notch7]

I think strong detergent followed by pressure water jet.

or use steam pressure jet.

I think you would need to be careful about damage using a high pressure washer, you dont want to blow the face off the bricks or take out the pointing.

 

[JonnyMercUK]

Struggling to see any mullions ...

They’re on the bay windows which are chopped off the picture

 

[JonnyMercUK]

I think strong detergent followed by pressure water jet.

or use steam pressure jet.

I think you would need to be careful about damage using a high pressure washer, you dont want to blow the face off the bricks or take out the pointing.

Any suggestions on a detergent?

 

[Notch7]

Any suggestions on a detergent?

Maybe a specialist stone cleaner like this from pure adhesion:

https://www.pureadhesion.co.uk/hanafinn-oxy-klenza-outdoor-stone-and-hard-surface-shampoo-1kg.html

 

[endecotp]

Building conservation people seem to advise against stone cleaning because it damages the surface of the stone which is detrimental in the long term, despite the short term improvement in appearance. This is obviously more of an issue for medieval castles that we’d like to still be there in another thousand years than for relatively modern houses that might get knocked down to build a Tesco in 20 years time...

I would suggest you do the least-aggressive treatment you can, e.g soapy water and a scrubbing brush, and see what you think.