I have recently purchased an old house (built in approximately 1900) in the United Kingdom as a renovation project.

The brickwork under the porch has been fairly well protected over the years and is still very clean. However, the brickwork above the porch and around the rest of the house has developed a black staining:

enter image description here

Would I be correct to assume that this staining is simply from rain?

In the coming weeks the house will have a scaffolding for other works and so I was hoping also to deal with this staining at this time.

Do you think it would be possible to restore the house brickwork to the original colour (as seen below the porch) and if so, what method(s) would be suitable to obtain this?

Thanks in advance

  • 1
    It's really hard to say what it is. It might be mold or mildew that is growing on the surface but it might also be some mineral that is in the brick that is oxidizing and staining the surface. You might try some things like bleach, mildew remover, and some acid wash on some small areas to see if any of them are effective.
    – jwh20
    Sep 29, 2020 at 11:43
  • 1
    There is a product used in the US called wet and forget. I have not used it on brick but have on wood siding ( I have also used hydrogen peroxide) if a form of mildew either product will clean 5% hydrogen peroxide works well for me cleaning organics , but normal dirt and grime the wet and forget worked better both with minimal work on my part.
    – Ed Beal
    Sep 29, 2020 at 13:56
  • Do you own the entire structure pictured in your photo, or do you only own one side or the other? If you don't own the whole structure and you only clean/restore your half it may end up looking more out of place than if you'd just left it alone ...
    – brhans
    Sep 29, 2020 at 17:50

1 Answer 1


Bleach works well . I dilute it 50 to 65 % and spray on red brick and concrete drive way. In my warm humid climate ,the brick gets green algae and some dark mold every year ( I usually need to spray only about 5% of the brick). The driveway gets dark ,apparent mold , and needs 100 % coverage. I use a 3 gallon hand pump garden sprayer. It will reach up about 20 ft.

  • It seems that I may just need to try different things from bleach, mildew remover, acid wash, mild hydrogen peroxide and I've seen steam cleaning suggested elsewhere. Thank you for your suggestion.
    – Dangerous
    Oct 2, 2020 at 12:38

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