Q. Our concrete sidewalks had a spotty mildew condition which now has erupted into a black walk. What will not only clean the walk but also prevent a recurrence of the mildew?There also is mildew on a newly painted building nearby. The painter was supposed to have added a mildew inhibitor to the paint. Shouldn't it have prevented the mildew on the building? Henry Block Beverly Beach, Fla.
A. The main problem with mildew is that it has to be killed, not just rubbed off. If not destroyed, it continues to spread with tenacity.
To thwart the mildew on the sidewalks, apply a solution of one gallon warm water, one cup household bleach, and one-half cup liquid detergent. Using a stiff-bristle brush, scrub the walks with the solution. Rinse thoroughly. Caution: Avoid spattering the mixture on nearby grass or plants, as it may harm them.
Now, about the mildew inhibitor that was supposed to have been added to the paint on the building. Even though the painter may have added a mildew suppressant to the paint, this would not necessarily destroy the moldy growth. If the mildew had not been thoroughly removed and killed before the painting, the application of paint with a brush or roller could actually spread the fungus over the entire surface.
Mildew is encouraged by shady, moist local conditions. Take it easy on sprinkling the grass that is next to the walk and building. Trim nearby trees and shrubs to let in the sun and fresh air. Remove grass clippings from the area.
Repainting the adjacent building walls may be necessary, but first be sure you have destroyed the mildew.