Algae or moss growth Algae or moss growth is the accumulation of living organisms on damp concrete surfaces. The growth often creates a slippery walking surface in shaded or consistently wet areas.
Algae and moss thrive where moisture remains for extended periods because of poor drainage, shade, or frequent water exposure. Although they do not usually damage the concrete itself, they can increase slip hazards for pedestrians. Correcting drainage and cleaning the surface help reduce recurring growth.
Frequently Asked Questions About Algae or moss growth
Why does algae or moss grow on a sidewalk?
Because moisture stays on the surface for extended periods, usually from poor drainage, heavy shade or frequent water exposure.
Does it damage the concrete?
Not significantly. The main concern is that it makes the surface slippery.
Is a slippery sidewalk a liability risk?
Yes. A slip caused by a persistently slick surface can support a claim against the property owner, even without a structural defect.
How is it prevented from returning?
By correcting the drainage or shade condition that keeps the surface wet, not just cleaning the growth off.