HOW TO PROTECT & RENEW CONCRETE

Stamped concrete should be sealed every two to three years to protect it from the elements, make it last longer and keep it looking new. My stamped sidewalk was looking dull and faded with a whitish film on it, so it was time to reseal.

Sealers are either water- or solventbased, and it’s best to use what was previously used on your patio. If you apply solvent-based over water-based, you’ll likely end up with an uneven, blotchy finish. That’s because solvent-based sealer will darken areas where the old sealer has worn off, but not areas where it’s still visible. If you put water-based sealer over solvent-based, you’re likely to get a poor bond.

I didn’t know what the existing sealer was, so I did this quick test. I poured some xylene—a readily available solvent— on a small area that still had old sealer. After a minute or so, it felt tacky, so I knew it was a solvent-based sealer. Water-based sealer gums up with this test. Switching to water-based sealer would have meant completely stripping the old sealer, which is a pain. So I stayed with solvent-based.

1 WASH THE SURFACE

I started by pressure washing using a surface cleaning attachment. The attachment has a spinning head, ensuring that I wouldn’t get lines in my concrete from a standard pressure tip. This step removes dirt, mold, mildew and old, flaking sealer. Some of the old sealer remained, but that’s fine. Think of it like scraping and repainting. You don’t have to scrape off all the paint, just the loose stuff. After the surface cleaner, I used a fan tip to rinse the dirt away.

I let the patio dry thoroughly, no less than 24 hours. If there’s moisture underneath the new sealer, it won’t bond well.

2 BLOW OFF THE DIRT

After drying and before applying sealer, I blew off any debris with a leaf blower. Sealing when the temperature is in the 60s or 70s degrees F is ideal. If the temp’s too high, the sealer might dry too fast and blister.

3 BRUSH THE TIGHT SPOTS

To apply sealer, I first brush areas that would be hard to reach with a roller, such as steps or where the concrete meets the house. Before applying the sealer, I mixed in an anti-slip agent called SHARKGRIP.

4 ROLL ON THE REST

I finished with a 3/8-in. nap roller, applying two thin coats. A thin coat of solvent-based sealer is ready for recoating in 20 to 30 minutes. You could apply sealer with a pump sprayer and then back-roll afterward, but you’d need a sprayer with hoses and seals that were made to stand up to solvent.