Simpson Strong-Tie Crack-Pac Flex-H2O Polyurethane Crack Sealer is a moisture-activated injection resin engineered to stop seeping and mildly leaking cracks, voids, and fractures ranging from 1/32 in. to 1/4 in. wide in concrete and solid masonry. The system is uniquely designed so that the polyurethane resin is packaged in the cartridge while the accelerator is packaged directly in the nozzle - meaning both components combine automatically upon dispensing, with no manual mixing required. When the resin contacts moisture inside the crack, it transforms into an expanding flexible foam that fills the affected area and delivers a lasting, watertight seal in both wet and dry crack repair applications.

Key Features

• Seals seeping or mildly leaking cracks - targets active water intrusion at the source, stopping leaks in concrete and solid masonry before damage spreads
• Dispensed with a standard caulking tool - no specialized equipment needed, keeping the repair process simple and accessible for a wide range of users
• Usable on dry cracks when water is introduced to the affected area - extends versatility beyond wet-crack scenarios so one product handles multiple repair conditions
• Accelerator amount can be reduced or omitted entirely - slows the reaction time when working conditions or crack geometry demand a more controlled application
• Expands to fill voids and seal the affected area - the foam conforms to irregular crack profiles, ensuring thorough coverage even in hard-to-reach fractures
• Fast-reacting formula - reaction begins within 1 minute after exposure to moisture, with expansion potentially complete within 3 minutes - minimizes downtime on the job site and reduces the window for continued water intrusion during repair
• 20:1 expansion ratio (unrestricted rise) - a small volume of material goes a long way, reducing the amount of product needed to fully seal a crack and lowering overall material cost per repair

Why This Product

• Built for wet conditions where other sealers fall short - the moisture-activated polyurethane chemistry means active seeping or mildly leaking cracks are not an obstacle but actually the trigger that drives the expanding foam seal, making this the right tool for waterproofing and water-intrusion repair in concrete and masonry structures
• All-in-one cartridge design eliminates pre-mixing - with resin in the cartridge and accelerator in the nozzle, the two components combine only at the point of injection, reducing waste, simplifying setup, and allowing a single operator to complete the repair with a standard caulking gun
• Flexible seal that accommodates real-world movement - unlike rigid fillers, the cured polyurethane foam remains flexible, helping the seal hold up in cracks that may be subject to minor structural movement or thermal cycling over time
• Proven for demanding environments including water and wastewater facilities - the approved applications confirm this sealer meets performance requirements in some of the most water-intensive conditions, giving buyers confidence in its reliability for both residential foundation repairs and critical infrastructure projects

Specifications

• MPN: CPFH09
• Brand: Simpson Strong-Tie
• Capacity: 9 oz.
• Material: Polyurethane
• Crack Width Range: 1/32 in. to 1/4 in.
• Compatible Substrate: Concrete, Solid Masonry
• Country of Origin: United States

Approved Applications

• Crack Repair: Non-Structural
• Brick: Solid
• Concrete Block: Grouted
• Concrete
• Water / Wastewater Facilities

What's Included

Each pack contains (1) CPFH09 Flex-H2 Polyurethane Crack Sealer, 9 oz. Crack-Pac Flex-H2O polyurethane cartridge (resin), Nozzle with accelerator.

Frequently Asked Questions

How does the Crack-Pac Flex-H2O work when injected into a wet crack?

When the resin encounters water as it is injected into the crack, it becomes an expanding foam that provides a flexible seal in leaking and non-leaking cracks. The polyurethane is packaged in the cartridge and an accelerator is packaged in the nozzle, so the two components combine upon dispensing.

Can this product be used on dry cracks?

Yes. The Crack-Pac Flex-H2O can also be used on dry cracks if water is introduced to the affected area, allowing the moisture-activated expansion reaction to occur.

How fast does the Crack-Pac Flex-H2O react after application?

The reaction begins within 1 minute after exposure to moisture, and expansion may be completed within 3 minutes, depending on the amount of moisture and the ambient temperature.

What tool is needed to dispense this cartridge?

The Crack-Pac Flex-H2O cartridge can be dispensed with a standard caulking tool, making it straightforward to apply without specialized dispensing equipment. The compatible tool is the Simpson Strong-Tie CDT10S.

Downloads and Resources

• Epoxy Crack Injection Guide
• Safety Data Sheets for Crack-Pac Flex-H2O