Drylok masonry sealant is commonly used to waterproof cracks in basement walls and floors. If you need to remove this heavy-duty coating, made by United Gilsonite Laboratories and often marketed as UGL Latex, you'll need the right solvent and a pressure washer powerful enough to blast away old layers of coatings. This combination, along with a little elbow grease, should strip old layers of Drylok in order to seal an old crack even better.

To properly seal an old crack, strip it down to see what you'll be sealing.

Step 1

Purchase the right industrial-grade solvent for Drylok removal. Drylok's patented latex formula makes it resistant to many common paint-removing solvents.

Step 2

Put on your gloves and goggles before you begin. Drylok solvent contains compounds that could damage your skin or eyes.

Step 3

Brush on your solvent to completely coat the Drylok. Let it sit for the time recommended on the container, typically at least 45 minutes.

Step 4

Turn on your pressure washer after the solvent soaking and see what can be sprayed away at top pressure.

Step 5

Use a sander to make tough areas more porous before trying a second coating.

Step 6

Use a sharp putty knife to help break up large swaths of Drylok.

Step 7

Brush on another coating of solvent and let it sit for 45 minutes before attacking the Drylok again with the pressure washer.