The safest way to remove mold, mildew and algae from pavers is a soft wash: a low-pressure application of a suitable cleaner, left to work, then rinsed. Avoid high-pressure blasting, which can strip joint sand and damage the surface. Prevention matters too, since growth returns wherever it stays damp and shaded.

Why do pavers turn green and black?

Algae, mildew and moss thrive where there is moisture, shade and organic debris. Humid summers, heavy rain and tree cover in Summerville and across the Lowcountry create ideal conditions. Green growth is usually algae or moss. Black or gray spots are often mildew or mold. They are more than cosmetic, because they make surfaces slippery.

How do you clean them safely?

•Sweep off leaves and debris.

•Wet nearby plants with water to protect them.

•Apply a cleaner made for outdoor masonry, following the label.

•Let it sit for the recommended time. Do not let it dry.

•Scrub stubborn spots with a soft brush.

•Rinse thoroughly at low pressure.

•Let the surface dry, then check the joint sand.

Test any product on a small hidden area first. Wear gloves and eye protection.

Soft wash or pressure wash?

•Soft wash pros: gentle on pavers and joint sand, and it kills growth at the source. Cons: may need dwell time or a second pass.

•Pressure wash pros: fast. Cons: can blast out joint sand, etch the surface and push water under the pavers, and growth may return quickly. If you use one, keep the pressure low and the wand moving.

What cleaners should you use or avoid?

•Paver-safe cleaners: products made for masonry and algae are the best choice.

•Mild soap and a brush: good for light growth.

•Bleach and harsh acids: use with caution. They can discolor pavers, harm plants and grass and set rust stains. Check compatibility first.

Rinse runoff away from garden beds, and keep cleaners out of storm drains.

How do you keep it from coming back?

•More sun and air: trim branches and shrubs that shade the surface.

•Better drainage: standing water feeds growth. The surface should slope away from the house, and a wet yard may need drainage work.

•Sweep regularly: remove leaves and debris before they decay.

•Re-sand joints: low sand holds moisture and invites weeds.

•Sealing: can help some pavers resist moisture and stains, but it depends on the paver, so ask first.

Patio maintenance, including soft washing, re-sanding and sealing, is a separate service from installation.

Frequently asked questions

 

•Is algae on pavers harmful?

It will not hurt the pavers quickly, but it makes them slippery and can stain.

•How often should I clean?

As needed. Shady, humid areas may need it more often.

•Will cleaning remove joint sand?

It can. Check and re-sand after cleaning.

 

•Planning a patio?

If you are in Summerville or the surrounding Lowcountry, we are happy to take a look. Every project starts with a free design and build estimate: an on-site visit, three price points for the same scope of work, and a custom 3D design once the project is booked. Every paver install includes a 10-year workmanship warranty. No pressure.