Directions & FAQs
Read entire can. Wear face and eye protection, protective gloves, and clothing. Make sure the surface is clean, dry, and free of grease, oil, and dirt. Shake well. Spray 8” to 12” from surface, using an even, sweeping motion. Apply multiple, even coats until ALL cracks and holes have been filled.
IMPORTANT: Allow 24 to 48 hours to dry before applying another coat.
Let it dry completely. (It usually takes up to 24 to 48 hours to fully cure.)
*Use Flex Seal ONLY in a well-ventilated area. When using inside, prevent vapor build-up by opening doors and windows. Ensure fresh air entry during application and drying.
*Do not use near heat, sparks, pilot lights or other sources of ignition.
Spray a larger area than area where the leak is and feather the edges. For best results, apply multiple coats rather than one thick coat and use at can temperatures above 60ºF.
Make sure Flex Seal has filled ALL cracks and holes and is FULLY CURED before testing product. If light can pass through, apply additional coats.
Frequently Asked Questions
Q: How long does it take to dry?
A: Dry time depends on the temperature, humidity, and thickness of the coating. Flex Seal will usually dry to the touch within 2 to 3 hours and fully cure in 24 hours. It will get stronger over time.
Q: How much will one can of it cover?
A: Depending on the number of coats and thickness, one 14 oz. can will cover up to 12 sq. ft. and one MINI 2 oz. can will cover up to 2 sq. ft.
Q: How much pressure will it withstand?
A: Flex Seal will withstand normal hydrostatic water pressure such as rainwater, but it is not made to withstand extreme pressure.
Q: Can I apply it on a wet surface?
A: Flex Seal can be applied on a wet surface, or moist environment in the event of an emergency. However, it will always adhere better to a clean, dry surface. To ensure its longevity, we recommend you reapply Flex Seal once the area is completely dry.
Q: How long will it last?
A: Depending on the environment, coats added, and maintenance, many people have found Flex Seal will last for years without cracking, peeling or losing any of its strength or sealing properties.
Q: Can I paint it on or brush it on instead of spraying?
A: Yes, you can spray the Flex Seal directly into a bowl and paint it, brush it or roll it on any area. However, we recommend using Flex Seal Liquid for these types of applications.
Q: Can I use it to seal the inside of a water tank used for drinking?
A: No, we do not recommend that you use Flex Seal on surfaces where it comes in direct contact with drinking water.
Q: Can I use it to fix radiators, tires or other areas with extreme heat and pressure?
A: No, Flex Seal is not made to withstand extreme heat or pressure.
Q: Can I use it on a gasoline tank?
A: No, Flex Seal should not be used to seal a gasoline tank, oil tank or any other flammable material.
Q: Is Flex Seal associated with GAF?
A: No, it is not affiliated with GAF and is not intended for use by Professional Roofers.
Q: Is Flex Seal Clear the same formula as Flex Seal Original and Brite?
A: In order to give Flex Seal Clear its amazing transparency, we had to make some adjustments to our formula. Therefore, the spray will be slightly thinner and multiple coats may be required to get the job done.
Q. Can I use Flex Seal Spray on vinyl pools and pool liners?
A. No, we do not recommend the use of Flex Seal Spray on vinyl.