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.

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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.