best way to clean deposits on brick?

Apologies if this has already been answered. I tried running a search, but there's a database error at the moment. Here's my question: How can I remove a white, scale-like deposit running down my brick wall beneath what is apparently a leaky or overflowing gutter. Power washer didn't put a dent in it. Suggestions? Thanks!

 

Powdery scale or hard scale? White or beige? Color of the brick?

 

It's hard enough to resist pressure washing, and it's white. It's on the red brick as well as the pointing, so it's likely coming from the roof/gutters. It's below the ridge where the two perpendicular roofs meet, and unfortunately, that's where the builder slapped the chimney, so the water flow there is pretty intense. The gutter probably can't handle it all.

 

I would use something like White Scum Remover by ProSoCo. Be careful and read all the instructions.

 

It sounds to me like it might be efflorescence, a scenario where water causes calcium hydroxide to leach out of bricks and mortar, individually, where at the surface, the CaOH becomes calcium carbonate, which is water insoluble and difficult to remove.

There seem to be some products out there to remove the deposits, but I'd imagine that they are all deleterious to the surface of the bricks and the mortar. (The most prevalent one is nasty muriatic acid.)

Also, since the deposits come from the bricks and the mortar, and not the water, but is caused by the water, you will not be able to fix the underlying problem until you fix the downspout and the running water. Every time the bricks get wet, and then dry, you will have deposits.

There is lots of information online about the problem. Here's a good summary from OSH, the hardware store: Orchard Supply Hardware - Article.

Jeff

 

Great posts - thanks for the help, guys!