Sequence of choices:
1) Powerwashing - safe, quick and easy. It removes dirt, mold, moss, etc.
Generally, It does not remove stains.
2) Bleach - dangerous to lawns & plants. It is also pretty harmful to
auto & home carpets when tracked in. Note that "dry" bleach is
still dangerous - the bleached area should be rinsed extremely well.
Bleach removes many stains such as the brown stains on concrete
from leaves in the fall. It also kills mold, moss, etc. It does not
3) Sandblasting or sand-entrained powerwashing. This removes everything
listed above since it works by removing a layer of the concrete itself
and everything attached to it. If used intelligently and sparingly,
it is somewhat safe, but I'd recommend it only as a last resort.
Any form of sandblasting is similar to using rubbing compound
(abrasive) to clean automobile paint - you are removing part of
what you are cleaning.
My sidewalk leading up to my front door is startin to get kinda dark. I cant
tell if its mold , mildew, or dirt...or all 3. but it definately looks like
its in there pretty good. is there some kind of brightener or bleacher that
works to help restore the original concrete look?
any info would be appreciated.