How do I clean algea from driveway?

Question

Green and dark spots on driveway

Answer 1

Brush it with a broom and a 10% bleach solution. RScott

Answer 2

You're going to think me daft for this, but it works, and works very very well.

First, power wash the entire driveway, focusing on the problem spots. Allow the driveway to completely dry. (For a one day job, power wash in the morning.) If you're concerned about the powerwasher eating up the cement, the wire brush will be very effective, just power wash the area after scrubbing.

Once the drive is completely dry, if you want to reduce the return of the algea, sealing the drive will help hinder it's return. You'll find this amazing, but if you've ever used the Amorall Tire Foam'n Shine or anything foaming in a can for getting your tires nice a clean, and black, you'll remember how the spots on the driveway didn't turn darker when it rained the next time.

Get 2 can's, foam an area and mop it in. Depending on the area, you might need a can or 2 more. My drive is a side entry and it took me 3 to do the whole drive. The next time it rained, my drive stayed white, just as if it never rained, and repelled the water amazingly well.

I'm sure there are other products that will do this too, but I found what works and I only have to redo it once a year if I want to keep it that way.

This nice thing is about this stuff, if you have any fluid leaks in the drive, they don't soak in and stain.

Answer 3

Treating mildew and algae.
Mildew and algae are quite common and easy to treat. Left untreated mildew and algae will stain your concrete. To treat the problem area, you will need a power washer, hot water and oxygenated bleach.
****Chlorine bleach can be used;**** *******however, it is toxic*********
** and should only be used in small areas where you can control the run-off.
Oxygenated bleach, also called sodium percarbonate, is very common and can be found at most hardware stores; it is usually sold as a deck-brightening agent. When it is mixed with warm water it becomes hydrogen peroxide, which is non-toxic and will not harm nearby plants and trees. Mix 2 parts hot water to one part bleach. Use this mixture in your power washer to spray the problem area. It's that simple. You should see immediate results. You may want to repeat this treatment periodically to keep the mildew and algae from returning.
http://www.essortment.com/home/removestaincon_sbbs.htm

Although this method says to use a power washer elbow grease works just as well. Using bleach can be quited harmful to lawns etc.as well as toxic to wildlife.
..........P.S. Special Tip..........
bakeries use bleach to remove mold and rope then they treat it with 5% vinegar to keep it from returning. Same thing with algae. I use to work for the largest independently owned bakery in the midwest. That's how I know.

Answer 4

Rent a pressure washer and spray the algea off. It should come off really easy. Its worth the money to not be out there scrubbing for hours.

Answer 5

Power wash it.
use vinegar - NOT BLEACH - as it is not harmful to the enviroment!