Regular foam cracks. Flex Foam flexes.

Flex Foam™ is a highly flexible, white expanding polyurethane foam that fills gaps and voids, insulates, and creates a water-resistant seal to help block moisture, drafts, pests, and noise. Its low-pressure, high-density formula expands to bond strongly without bowing or warping and stays flexible after curing, moving with surfaces instead of becoming brittle over time. The cured foam is trimmable, sandable, paintable, and stainable for a clean, seamless finish.

Most expanding foams fill gaps well at first, but over time, they dry hard, crack, and lose their seal as structures shift and settle. Flex Foam’s low-pressure, high-density formula cures into a highly flexible, rubber-like structure that moves with the surface instead of fighting it. The result is a seal that holds up through movement, vibration, and temperature changes without cracking or crumbling.

Flex Foam™ is available in a net wt. 12 oz. can in Bright White.

Flex Foam™ is a one-component polyurethane foam, no mixing required. When dispensed, it expands to fill the gap, then moisture in the air triggers the curing process. The result is a high-density foam with a structure engineered for both strength and flexibility.

Flex Foam™ works on wood, brick, metal, stone, vinyl, PVC, concrete, block, and more. It may not be compatible with some plastics. We recommend testing in a small, inconspicuous area first on any surface you are unsure about.

We do not recommend Flex Foam™ for polyethylene (PE), polypropylene (PP), PTFE, and certain other low-surface-energy plastics. It is also not intended for continuous water immersion. When in doubt about plastic compatibility, test a small area before full application.

Flex Foam™ is designed for indoor and outdoor use. Common applications include windows and door frames; basement, attic, and crawlspace gaps and penetrations; plumbing and HVAC pipe penetrations, pipe insulation, utility pass-throughs, and duct openings; roof joints, soffits, fascia, and siding gaps; brick and concrete gaps; spigot and other exterior penetrations; areas exposed to settling, movement, or vibration; and pest entry point blocking and sound dampening.

Yes. Flex Foam™ is a long-lasting solution for a wide range of indoor and outdoor applications.

Always wear eye protection, gloves, and proper work clothing when using foam. Cured foam is difficult to remove from skin, clothing, and other substrates.

1. Area should be clean, dry, and free of grease and oil.
2. Shake can for 60 seconds then immediately attach the straw applicator. Test the pressure and expansion rate before beginning project.
3. DO NOT overfill gaps and holes. When applying foam, only fill crevice up to 50% as foam will continue to expand after being dispensed.
4. For best results, always invert can while dispensing. This ensures complete delivery without clogging.
5. Tack-free in 10–15 minutes, fully cures and ready to trim, sand, and paint in 8–12 hours.
6. For waterproof and UV protection, we recommend adding a topcoat of Flex Seal® spray or liquid.

Flex Foam™ comes with a precision nozzle applicator, so no additional application tools are required. Always wear eye protection, gloves, and proper work clothing. For finishing, a utility knife works for trimming, and standard sandpaper works for smoothing cured foam.

The optimum application temperature is 68–77°F (20–25°C). Approved for application temperatures of 32–95°F (0–35°C).

Flex Foam™ is tack-free in 10–15 minutes and is fully cured and ready to trim, sand, and paint in 8–12 hours.

Once cured, Flex Foam™ performs in temperatures ranging from −40°F to 176°F (−40°C to +80°C).

Yes. Once fully cured, Flex Foam™ can be trimmed with a utility knife, sanded smooth, painted, and stained. We recommend covering any foam exposed to direct sunlight with paint, stain, or a topcoat of Flex Seal® spray or liquid to protect against UV degradation.

Flex Foam™ is water-resistant and weatherproof. It helps seal out moisture and drafts. It is not intended for continuous water immersion. For waterproof and UV protection on exterior applications, we recommend a topcoat of Flex Seal® spray or liquid over the cured foam.

Yes. Flex Foam™ provides both thermal insulation and acoustic insulation, helping reduce energy loss, drafts, and noise transmission through gaps and penetrations.

Yes, Flex Foam™ helps reduce sound transmission and absorbs vibration, making it useful for sound-dampening applications around pipes, ducts, and structural penetrations.

Fresh, uncured foam can be removed immediately with a multipurpose foam cleaner or cleaning wipe. Cured foam can only be removed mechanically. It cannot be dissolved once cured.

Store the can upright in a cool, dry place between 41°F and 77°F (5°C and 25°C). Do not expose to temperatures above 120°F (50°C), freezing conditions, or direct sunlight.

After using Flex Foam™, leave the applicator nozzle attached. This will allow the foam inside to cure, creating a plug for storage. When you’re ready for your next project, remove the old nozzle and replace it with a new one before use. Additional flexible applicator nozzles are sold separately.

Flex Foam™ has a 12-month shelf life when stored between 41°F and 77°F (5°C and 25°C).