APPLYING SEALER ON A 15YR OLD SLAB

by Matt
(Ohio)

Question: I would like to apply a sealer on a pad that my camper sits on. I am not sure what was used originally, if anything. I want something that will hold back mildew and have some shine. Is there such a product?

Answer: Matt, if you sprinkle or spray some water on the concrete and it soaks into the concrete & darkens it in 15 - 60 seconds, then you can be pretty sure there was no sealer applied to the pad or if there was it has worn off.

You'll have to do a few steps to get the results you're looking for.

First: Clean the concrete by washing it with simple green or dawn dish detergent, a scrub brush, and a pressure washer.

Second: Let it dry for 24 hrs then you can use a penetrating, moisture blocking sealer called Radonseal to seal the concrete and block any moisture from coming up through the concrete from the sub-base.

A simple pump up sprayer works best to apply this sealer. It's viscosity is like water so it sprays really easy.

This sealer is all you need to do to seal the concrete. But if you want a shine, you'll have to do one more step.

Third: To get the "shine" you're looking for, you'll have to apply a topical acrylic sealer. They come in water-based versions and solvent based versions. I like the solvent based better myself, I think they're more durable for exterior applications.

You can use any solvent based acrylic sealer with about 23% solids to achieve the "shine" or "gloss" you're looking for. I use a sealer from Butterfield Color called "Clear Guard Pro 350 Cure & Seal". You can find a distributor on their home page or you can go to a Sherwin Williams store and use their solvent based sealer.

After step 2, let the concrete dry for 48 hrs and apply 2 light, thin coats of the acrylic sealer. You can roll it on with a 3/8" nap roller or spray it on with a pump up garden sprayer. Keep the coats light and thin, thicker is not better, it