How can I clean old brickwork without doing damage?

[michael]

Can anybody suggest the best way to clean old brick work (about 190 years old) One elevation of my property has a two tone colour scheme of predominately red brickwork with about six courses of yellow brick up from the ground, yellow brick edging on the corners of the property and yellow brick arches over the windows.
Unfortunately much of the clarity and richness of this detailing has been lost to the grime that has caked itself onto the surface over the years. I suspect that this grime is old soot deposits combined with sea salt as I live near the coast and not in a particularly built up or traffic congested area.
Obviously I don’t want to use anything to harsh on these old bricks so I want to avoid sand blasting. I’m even wary of using chemicals.
Once when I hired out a power washer to clean a pathway, I experimented by aiming the washer at a particularly dark patch on the wall just for a few seconds. It made the wall very wet but didn’t budge the grime. In any case I think too longer blasting with a power washer could over saturate the bricks and even dislodge the pointing. Any other suggestions for returning this old brickwork to its former glory would be appreciated.

 

[inwood]

Strippers of Sudbury are my preferred choice. They have some great products and specialise only in the production of paint removal products.

http://www.stripperspaintremovers.com/

One of the photos on the leaflet the enclose with their products shows a before and after of a very large old brick house which had been painted in white. Very impressive (the after photo that is!).

Give them a call. If the jobs big enough I think they're happy to send out consultants to advise.

They don't just do paint removal - they also have a poultice based system which is very good at removing soot deposits.

 

[Nemesis]

This isn't paint though, it's muck and pollution. Hard to shift.

Have a look and see if your local authority has info on its website or give your CO a ring to see what he or she recommends.

Here's a starting point:

http://www.eastherts.gov.uk/index.jsp?articleid=2573


I agree - don't pressure wash or blast!

 

[inwood]

Nemesis - I edited my response as I realised I didn't make it clear they don't only do paint removal.

As I mentioned above in my updated post the poultice based system is very good at getting rid of soot.

 

[Nemesis]

Sorry - didn't see that bit when I posted!

SPAB has a technical leaflet about brick cleaning too.

I haven't tried Strippers muck removal, but as with all chemicals it's something to test in a small area first. Some bricks are softer than others.

Also - overcleaning can make a building look very odd, it's all a balancing act really, getting rid of the grime without the patina of age.

Sounds lovely brickwork though.