How To Seal Crawl Spaces, Basement Windows, and Pet Doors

Our video below will maximize your success when preparing for a flood using the Flex Seal Flood Protection line. Crawl spaces, basement windows, and pet doors can all vary in shapes and designs, so it's important to seal any areas where water may enter.
Always follow evacuation orders. Heed all directions from local government and emergency management officials. Watch our introductory video before starting.
Products Used:
Flood Protection Paste (Sleeve)
Flood Protection Liquid
Tools Used:
• Caulk Gun
• Flex Gap Filler Tool
• Paint Brush
• Putty Knife
• Protective Gloves
• Eyewear
Flood Paste in a Cartridge is the base coat for your first layer of protection. Use a gloved finger, Flex Gap Filler tool, or similar tool to push into all seams and openings to help create a watertight seal. Always be cautious of any sharp objects that may cause injury.
Apply Paste
Measure the opening you want to seal. Cut a piece a plywood large enough to overlap the entire opening. Apply a generous amount of the flood paste to the wall surrounding the entire opening.

Firmly press the plywood to the wall, covering the entire opening. The Flood Paste should squeeze out between the plywood and the wall. If not, you’ll need to apply more Flood Paste.

Brace or hold the plywood in place for a few minutes until it stays in position. Once in place, use a gloved finger or Flex Gap Filler tool to push the Flood Paste into the seam between the plywood and the wall and smooth out, making sure there are no gaps or openings.
Additional Layers
If you applied Flood Protection Paste in thin, even layers, you should expect it to be dry to the touch in two to six hours.

Once the plywood is sealed and completely dry, and you already have multiple layers of Flood Protection Paste, we recommend using our Flood Protection Liquid as additional layers of protection.

Brush a generous amount of Flood Liquid directly on top of the plywood, as well as the surrounding areas, making sure to overlap where the Flood Paste meets the wall.

Follow the same application process as the first layer, but each individual coat that you apply should be wider and overlap the previous layer of Flood Protection Paste and Liquid.

Remember you want to make sure all the flood protection products are fully cured before a flood arrives.

For additional help, click on one of our how-to options below, or call us at:
833-4-A-FLOOD (833-423-5663).

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We’re proud to say that when used in combination, and as directed, our Flood Protection Products have been independently verified by UL Solutions to hold back 3ft of water for 14 days on gaps up to ½ inch. Tested in laboratory settings.
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‍Our dedicated Flood Protection Product support is here when you need it. Whether you have questions about our products, or need help ordering, our experts are ready to help.

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