After the foundation crack has been identified and determined to need repair, the first stage of the repair process is the "drilling".

For HPI or "high pressure injection", a series of 3/8" diameter holes are drilled from the bottom of the crack (starting approx. 1" above the floor) and continue all the way up to the sill plate at the top of the foundation. These holes are drilled along side the crack about 3" to either side at an angle of approx. 45-55 degrees. This is imperative as the "vein" of the crack must be intersected at a depth of approx. 4" into the 8" thick wall. This will ensure optimum Polyurethane Resin penetration at the injection stage.

On average, there will be between 18 and 20 (average spacing of 5-6") injection points on a typical crack. The last step of the drilling stage is to flush out any drilling dust/debris from the holes with water.

This stage in the repair requires the installation of the "Injection Packers and Zerks" (nipples).

The 3/8” Plastic Injection Packers are designed specifically for high-pressure resin injection  using 3/8” angled drill hole techniques. The Injection Packers are specially constructed of high impact virgin Nylon and the removable zerk grease fitting acts as a one-way check valve.

The plastic packers must then be hammered into the drill holes until each one is securely in position.

Lastly, a 5/16” nut driver in a low speed cordless drill is used to screw the zerks (grease fittings) into the plastic packers. Over tightening and stripping the threads must be avoided so their integrity is not compromised.

At the Flushing stage, a high pressure pump is connected to each Zerk one at a time, and a food grade acid/water mixture is flushed into the crack at approx. 3000 psi, starting at the bottom and ending at the top of the crack. After the acid/water flush cycle is complete, a water rinse is implemented but in reverse, starting at the top of the crack and hitting each Packer all the way to the bottom.

A lot of companies may skip this stage because of the cost of a high pressure pump and the time factor. At Pro-Leak Solutions, this step is ALWAYS done and here are the reasons why:

  1. When "Flushing", you will only see the acid/water being forced out of the actual crack if and only if the vein of the crack was intersected during the drilling stage. If a particular Injection Point does not seem to flush well, then another can be drilled on the opposite side of the crack in most cases. This eliminates a "dud" hole that will not be able to introduce the Polyurethane Resin during injection.
  2. Every time a crack indicates signs of water leaking from it, or puddling on the floor, that in turn means the crack will be full of outside sediment and debris as it travels in with the water. Imagine trying to lay tile or paint a dusty floor...there will be very poor bonding and adhesion, if any at all. By Flushing, the entire interior of the crack is properly cleaned and prepared for Resin adhesion.
  3. The acid/water solution is mixed at a concentration just strong enough to "etch" the concrete interior of the crack from top to bottom. This "etching" essentially creates a rough bonding surface for the Polyurethane Resin.
  4. The "Water Rinse" afterward, leaves the crack clean and damp throughout. This is a desired condition prior to Injection as the Resin is actually Hydrophobic (water activated) and will expand upon contact with moisture.

The application of a hydraulic cement barrier over the face of the entire crack is the next step.

 Like "Flushing", the "Cementing" is unfortunately another important step that can often be disregarded by other companies because of the cost factor for hydraulic cement and the sheer time it takes to mix and apply it properly.

At Pro-Leak Solutions, we apply a 1" to 1.5" thick layer of hydraulic cement along the entire crack and feather it out approx. 2" on either side. A misconception is that this cement layer aids in preventing water from re-entering the doesn't. The sole purpose of this very important step is to provide "resistance" on the interior wall.

Due to the high pressures at the Injection stage, it is ideal to have some sort of a resistance barrier inside that acts similar to the forces exerted by the earth on the exterior of the foundation. This in turn, creates a "sandwich" effect allowing the Resin to be pressurized throughout the entire length of the crack and through the 8' thickness of the concrete foundation.

The High Pressure Resin Injection is the final stage of the repair.

The final step leading to a permanently dry crack is the injection of top quality Polyurethane Resin. A single component, hydrophobic

polyurethane injection resin designed for sealing leaks through cracks, rock pockets, expansion and control joints in concrete structures is introduced to the crack at approx. 1000 psi.

This resin and accelerator mixture reacts when it comes in contact with water and forms a micro cellular closed cell gasket with excellent adhesion and long-term flexibility. The flexibility factor is of the utmost importance as the Canadian climate is subject to very extreme freeze/thaw cycles which leads to constant movement in concrete structures and foundations. The cured hydrophobic compression gasket that is formed in the joint or crack remains stable and is highly resistant to degradation resulting from repeated freeze/thaw and wet/dry cycles.

Quite typical and very common in High Pressure Injection repairs is to see some cured resin being forced out the sides or over the top of the hydraulic cement barrier. Again, the barrier's sole purpose is to provide resistance for the approx. 15 minutes it takes the Polyurethane to change from its injected liquid state to a solid state.

It is optional but usually unnecessary to remove the cement and packers after a repair. If desired, the cement layer can be chiseled off quite easily and a sharp knife or reciprocating saw can be run down parallel to the face of the wall, sheering off the protruding tips of the packers.

Unless landscaping, high grade, interlocking or patterned concrete are on the exterior of the foundation where the crack is, there will most often be signs of the cured Polyurethane Resin penetrating to the exterior. In some cases it may not be visible even though the crack was completely filled but does NOT mean the repair will be compromised in any way.