Flex Seal Liquid for Basement Waterproofing

Does your basement look more like an indoor pond? Mother nature has her way of turning basements inside out, but the Flex Seal Family of Products is here to change the basement waterproofing game. Luckily many Flex Seal users have had great success with using our products in waterproofing their basements. We’ve received hundreds of 5 star reviews, check out a couple of them below:

“Over the last few winter snow melts we noticed more and more wet areas in our basement. Just prior to this past winter we used a gallon of the clear Flex seal. When the snow melted in the spring we observed less water than previous spring melts. We decided to purchase 4 gallons of the gray Flex seal. In all we have purchased 8 gallons and have done 2 coats of Flex seal over our entire basement.

In the last month we have had several downpour rainstorms and have yet to see ANY water in the basement!

– Amazon Customer


“Put this on a basement wall with a hairline crack from top to bottom and mud was washing in at the bottom.. We hoped it would fix the problem since a relative had the same problem and it cost them $12,000. to fix their basement. we sanded the crack and applied this to the entire crack pretty heavily. waited a few days and applied a second coat.

This week it rained for three days, without this applied to wall we would always have water and mud run across the floor. we have checked it several times and ‘NOTHING’

We are so excited about this product. I was skeptical but it seems to be hold back the leak. I wish we had heard about it a year ago before the water and mud ruined the paneling and floor in that room.”

– Alma Atckinson, Amazon Customer

Be sure to stock up on Flex Seal Liquid, along with a paint roller, paint tray and a drop cloth. For hard to reach areas, you may also use Flex Seal or Flex Shot.

1. Identify the Leak Immediately

Find the moisture or source of the leak in your basement. Water and moisture have several sneaky ways of seeping into your walls. Once you’ve done this, you’ve won half of the battle. Check for things such as pipe leaks and make note of any wet areas after a heavy rain. Wet basement walls can cause humidity levels to rise around the house, create foul smells or even mold and mildew growth. To avoid this domino effect, make sure your basement waterproofing efforts are done correctly and with the most reliable products the first time.

Don’t forget to check for other sources of leaks besides just the walls. This includes window leaks, washing machines and plumbing. All of these examples can lead to more water intrusion. Flex Shot and Flex Seal Spray are great options for use around a window sill, or other areas you might not be able to reach with Flex Seal Liquid.

2. Clean the Surface

Before applying any of the products in the Flex Seal Family, wipe down the surface. It must be clean of any grease, dirt, oil, mildew, or mold. (Bleach and water can be used to scrub away mold). Let your surface dry before moving on. You want to apply your Flex Seal Family of Products to a clean surface for the best basement waterproofing.

Be sure to check for things outside of your home that may cause your basement to collect moisture. Consider extending downspouts away from the home. Do not let rainwater collect near the foundation. You can use products in the Flex Seal Family of Products to help with this, such as Flex Glue to secure an extension, or Flex Seal Liquid on the ground to move water away.

3. Apply Flex Seal Products

Flex Shot and Flex Seal Liquid are great options for attacking a basement wall leak. Flex Shot includes an easy to use extension tube that makes it easy to get into corners or other tight spots. Use a drop cloth on the floor first, for easier clean up. Pour the Flex Seal Liquid into any larger cracks, then you can use a roller or brush to cover larger areas. Be sure to apply several coats and cover the area as much as you can. For best results, allow 24 hours for each coat to dry. It may be difficult in a basement, but try to keep the area as well ventilated as possible.

By using these tips you can greatly reduce the amount of seepage and leaks in your basement. Many other products in the Flex Seal Family are waterproof, so consider using Flex Glue, Flex Tape or Flex Seal Spray for other areas that may be experiencing water intrusion, or other repairs around the basement.