Liquid Concrete Crack Filler

The Foundation Armor Concrete Repair Kit is a liquid polyurethane resin concrete crack filler that expands up to 40X its volume when it comes in contact with water. The liquid concrete crack filler, when it reacts with water, turns into a polyurethane foam that creates a strong, permanent bond to the concrete.

Used by industrial, commercial, and now residential clients globally, the Foundation Armor Crack Repair kit will repair cracks in interior and exterior concrete, brick, or cement. When injected into the crack, it reacts with water to create a foam that expands 40X its volume. It bonds to the concrete to create a permanent seal that will stop water, efflorescence, insects, and radon. It can be used on dry, wet, leaking, and gushing cracks.

How To Use The Polyurethane Crack Repair Kit

How to repair cracked concrete using the Foundation Armor Concrete Repair Kit.
Approximate prep time: 5 Minutes for 10FT of cracked concrete
Approximate repair time: 10 minutes for 10FT of cracked concrete


Furnish all labor, equipment, and materials necessary and incidental thereto to perform all required operations to eliminate the flow of water by pressure injection to fill cracks, voids, and joints in concrete substrates.

Definition of Terms

Refusal – when a crack or void area will accept no more grout under the prevailing pumping conditions (for reasons other than the pump-ability of the grout).

Return time -the time taken for a grout, under certain application conditions to completely penetrate a crack, void, or network of cracks.

Gel time – the time required for the grout to cure following the reaction with the accelerator. Gel time or cure time can be affected by temperature and amount(percentage) of accelerator mixed in the component A.

Adding Accelerator

The most commonly used hydrophobic is a polyurethane resin, which is accompanied by an accelerator. The applicator/contractor is able to adjust reaction times based on flow rate and application variables. This is achieved by adjusting the amount of accelerator accordingly in the range of 2-20%. For gushing leaks, 20% accelerator solution will provide immediate results while most common crack leaks are repaired with a 5% solution. This is roughly 7oz. of Foundation Armor accelerator per 1 gallon of Foundation Armor polyurethane resin. After mixing, the polyurethane is ready for injection.


Fully examine the existing site conditions to ensure that all associated work can be performed without removing or relocating existing utilities, structures or structural members.

1) Wear adequate protective gear and goggles at all times, and follow data sheet and MSDS Instructions.

2) Thoroughly clean the face of the crack or joint by wire brush, disc sander, pressure washing, or similar. It is recommended to inject into the cleanest substrate possible for optimal results.

3) Identify the drill hole spacing and depths.

  1. Spacing: Drill holes should be 6-12 inches apart (6″ for hairline and 12″ for wider cracks). Alternate positioning from left side to right side as you move along the crack where possible.
  2. Depth & Angle: Drill at a 45° degree angle where possible to intersect the wall/floor joint interface halfway through the thickness of the substrate (e.g. 4″ deep for 8″ thick slab) Drill straight into the crack for concrete thickness below 4 inches. Drilling depth should be half the thickness of the concrete member.

4) Before installing mechanical injection ports, you must confirm that the hole is accepting water. Add water into the hole. If the hole is accepting the water, the water should enter in through the drilled hole and escape into the crack. If the hole is not accepting water, you 1) may need to drill deeper, or 2) the crack is directed into the opposite side (which means you need to drill from the opposite side of the crack and water test again. (Note: Do not inject water using the pump included in this kit. The polyurethane is water activated and it will cause pump failure if there is water in the pump).

5) Once you have confirmed drill holes are accepting water, install mechanical injection ports and secure in place. These packers have a threaded shaft with a rubber base. Following insertion, tightening of the threaded shaft will compress the rubber inside the drill hole, resulting in a compression seal through which you will inject the polyurethane resin.

6) Begin injecting from the lowest packer. Under proper pumping conditions, the following signs should be observed in the order listed:

(a) Water displaced from crack/joint by the resin (if you have a dry crack, add water to the crack)

(b) Water and resin mix (foamy) appearing at the crack/joint area

(c) Pure resin from crack/joint

If the joint surface exhibits immediate free flow of resin while working the first packer, pause for a few minutes. In most cases the resin will react fast enough with the water and expand rapidly. The resulting resin product will heal the joint and provide a surface seal to contain the material to follow. The applicator/contractor is responsible for estimating what duration time is adequate for grouting the voids and is responsible to prove that the void is full by attempting to inject each port to refusal.

Once the applicator/contractor is assured that the resin has reached the next injection packer or has sufficiently stopped the water as evidenced by the grout oozing out of the joint area, he should shut off the resin flow and disconnect pump pressure line and proceed to the next packer. Follow the injection process for one to three packers, the applicator/contractor shall return to the first packer and attempt to re-inject it again. Some of the packers will take more grout, filling up more of the crack/joint area and creating a higher density void filler and water stop. The applicator/contractor shall continue this procedure until refusal.

7) Make sure the above procedure has been repeated until the entire length of the rack or joint is sealed.

8) After allowing the material to fully cure overnight if possible, packers can be removed by loosening the shaft. Some applicator/contractor leave the rubber base in the wall and then patch the drill hole while others remove the entire packer prior to patch. In some remote injection applications packers even remain in place permanently. This is applicator/contractor preference. A final cleanse of the face of the crack is necessary to remove cured product via wire brush, pressure washing, etc. The substrate is now ready for final finish to applicator’s/contractor’s intention.

9) Flush all dispensing equipment initially with a small amount of solvent such as xylene or acetone to cut the product (if permitted on the job). Do not use solvent for the final flush as it will diminish the life of your equipment drastically. Do NOT clean with water!!! Store for next use.

Foundation Armor Injection Gun Instructions

Manual Filling

Before filling gun with material pull plunger rod to the full extend and push back into the cartridge. This moves the plunger inside to the end of the cartridge barrel and ensures a tight seal. Tighten the rigid nozzle and zerk coupler. Unscrew the pump unit from the cartridge barrel. Keep the opening of the barrel upright while carefully filling with the premixed injection material. Slight leakage at the plunger rod is possible.

Re-connect pump unit and cartridge tightly and immediately turn the gun with the nozzle directing towards the floor and the plunger rod pointing upright.


The pump unit relies on gravity to feed the cylinder inside with material. Therefore during the injection process and at all times when the gun is charged point the nozzle towards the floor. This permits the resin inside to flow into the cylinder. While pumping resin make use of the full stroke permitted by the handle. Insufficient stroke does not permit optimal fill of the cylinder resulting in reduced pumping volume and pressure. Always point the nozzle downwards.


The unit can be cleaned for repeated use. Do not use water to clean the gun.

Please observe caution when operating the gun. Read and understand all data sheets and MSDS when using injection materials.

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