Ingrained grime in brickwork

[michael]

I used some Wickes Fast Acting Patio Cleaner the other day to remove some stubborn and slippery grime and green algae that had accumulated in a dark, shadowy and often damp corner of the patio. It worked a treat. You apply it, scrub with a nylon brush, leave for ten minutes, then wash down. It got me wondering, if used sparingly and applied with a paint brush, whether it would be suitable for cleaning an area of ingrained grime (probably dirt and soot) on an area of brickwork to the rear of my early 19th century home which gentle scrubbing with soap and water has so far failed to remove. This Wickes stuff claims to be suitable for use on concrete, brick and natural stone but I suspect they don’t mean 195 year old bricks. The active ingredients do sound quite harsh but then again they only make up a small percentage of the mix. They are:-
Hydrochloric Acid - Less than 5%
C9-C11 Alcohol Ethoxylates – Less than 5%
Quaternary Coco Alkyi Methyl Amine Ethoxylate Methyl Chloride – Less than 5%

Just writing this I can feel you all cringing and I’m getting a strong premonition of you all screaming “NO WAY. DON'T DO IT”

 

[MdB]

If brickwork is held together with cement then maybe. (I've no idea what it will do to old bricks - may not be a good idea)

If brickwork is held apart by lime then it won't be for long if you add an acid to it. It will likely bubble nicely for a while though

 

[plasticpigeon]

Please take others' advice, but there is something important when using this with old bricks. The bricks must be wetted down considerably before hand so that they are wet, because otherwise the acid will get absorbed into the bricks, and really the purpose of the acid is just to clean the surface. It will also erode the lime mortar as mdb says. I tried it out and it didn't erode the mortar much, but did make it darker, presumably because the surface layer was more sandy and had less lime in it.

 

[Stevie816]

Incredible but true.
When we had our stove replaced there was hundreds of years of soot etc on the back brick wall from when there was no liner.
While I was pondering and researching how to clean it off. My wife cleaned it off with fairy liquid, water and a small brush.
The result was amazing and there is now just a feint stain. I had to clean the rest of the fireplace as the back was so clean it made the sides look grubby.
So one afternoon a lot of hard work and soapy water worked for me. we started with a scraper to get the worst lumps off then a stiff brush then soapy water
Just keep changing the water a be patient. A few beers helped
Steve816

 

[LadyArowana]

Some very common products do work extremely well. I have dreadful ceramic tiles on the kitchen floor that don't have a resistant glazed surface and they stain instantly when anything like beetroot or curry is splashed. If I brush a foam of ordinary cake handsoap onto the tile and leave it for about 10 mins the surface is completely clean when wiped down. I used the same method in an old bathroom a few years ago and it removed nasty stains without much fuss.