Published on December 11th, 2013 | by Henri0
Green spots on concrete patio
Q. I live in a townhouse with a 10-foot by 10-foot concrete patio. The concrete has greenish-colored spots that appear to be moss or mold growing into its porous surface.
I’ve used a 2-to-1 mixture of hot water and bleach, and scrubbed the patio. This removed all the dirt but the greenish spots remained. What is this? Is there a simple and easy way to remove these spots? The patio faces west and does receive full afternoon sun.
A. Try a mixture of equal parts water and fresh Clorox bleach (it contains chemicals other brands may not have). Pour it on and let it stand for a few minutes to see if it gets rid of the greenish spots. If it does not, increase the ratio of bleach to water and try it in one spot. Once you have succeeded, you’ll probably have to bleach the entire patio so it will have an even color.by