Whats on my shingles & how to remove it?

[david norton]

Hi all,

Just bought a new house and am eager to get the siding in order.

The shingles are pretty discolored. Mold/mildew . . . and pretty stubborn. I have tried some scrubbing, pressure washing - tried Cabot cleaner and even diluted bleach. This stuff is STUBBORN.

Any ideas on how to remove or at least how to get a semi uniform look here?

 

[Ian]

Have you tried some of the specialist black mold removers? It looks pretty baked on, so may be problematic to remove.

I'd have tried a fairly strong mix of Sodium hypochlorite (bleach) and water, applied with a garden sprayer and left for an hour or so, then scrubbing it and giving it a good rinse. Just be careful to wear protective kit, as it can be nasty stuff. It sounds like you may have already tried this though.

 

[chopnhack]

Mold stain is very difficult to remove. Pressure washing should be avoided as it will scour the soft wood. 4:1 bleach to water or as they now recommend the oxygen based bleaches are preferred. The trick is letting the chemicals do the work, i.e. - work a small area at a time and keep it flooded with the wash solution. Use a softer type bristle broom or brush, if you see fuzziness, the bleach solution is too strong, add more water (the fuzzies are wood fibers)