[ Solution ] Basement Waterproofing Est. 2009

Wall Crack Injection: Sealing Foundation Cracks Permanently Without Excavation

Polyurethane foam injection expands to fill a crack through its full depth and thickness, creating a flexible, waterproof seal that lasts for decades.

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Method Spec Wall Crack Injection
Process
5 steps
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Workmanship Warranty
Inspection
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On cost: $300 to $800 per crack depending on length and material used

Overview

Wall Crack Injection

Wall crack injection is the most targeted and cost-effective solution for stopping water entry through isolated cracks in poured concrete foundation walls. The process uses either polyurethane foam or epoxy resin injected under low pressure directly into the crack, where it penetrates through the full depth of the wall and cures into a solid, waterproof seal. Unlike surface-applied patches or hydraulic cement that only seal the interior face, injection materials fill the crack through its entire thickness, including hairline extensions invisible from the interior. For Middle Tennessee homeowners dealing with the inevitable shrinkage cracks in poured concrete walls, or with cracks opened by frost or clay soil pressure, polyurethane injection provides a permanent repair without the cost and disruption of exterior excavation. Ground Up Foundation Repair uses moisture-activated polyurethane foam for active water-bearing cracks and high-strength epoxy resin where structural bond restoration is also required.

The crack is first cleaned and assessed to determine its width, depth, and whether water is actively flowing through it. Surface ports are attached to the wall face at intervals along the crack, spaced based on wall thickness and crack width. A low-pressure injection pump introduces the repair material through the ports, starting at the lowest port and moving upward. For polyurethane foam, contact with moisture in the crack triggers an expansion reaction that drives the foam deeper into the crack and fills all connected voids. The foam expands several times its liquid volume, ensuring complete fill. For epoxy injection, the resin cures into a rigid bond with tensile strength exceeding that of the original concrete. Once injection is complete and the material has cured, the surface ports are removed and the exterior faces of the ports are patched flush with the wall surface.

Wondering if this is the right fix for what you are seeing? Learn more about the warning signs: Basement Flooding and Basement Water Intrusion . Or browse the full Problem Signs library for basement waterproofing.

Installation Process

How we install wall crack injection

Crack Assessment and Cleaning

The crack is wire-brushed and vacuumed to remove dust, dirt, efflorescence, and any previous patching material that would prevent bond or block injection flow. The crack width and orientation are documented to determine appropriate port spacing and injection material. Any surface debris that would prevent port adhesion is removed from a 2-inch band along the crack.

Injection Port Placement

Surface injection ports are adhered to the wall face at intervals of 8 to 12 inches along the crack, centered over the crack opening. Port spacing varies with wall thickness; thicker walls require closer spacing to ensure complete fill. At the ends of the crack and at any intersecting cracks, additional ports are placed to ensure the entire crack system is pressurized.

Port Sealing and Surface Cap Application

An epoxy surface cap material is applied along the crack between ports, sealing the surface of the crack so that injection pressure forces material through the depth of the wall rather than out the face. The cap is feathered thin enough not to prevent the injection material from flowing within the crack, only to seal the face.

Material Injection

Starting at the lowest port, injection material is pumped at low pressure until it is seen emerging from the next port up the crack. That port is then capped and injection continues at the next port. This sequential process ensures the crack is filled from bottom to top without air pockets. For active water cracks, moisture-activated polyurethane is used. For dry structural cracks, high-strength epoxy is injected.

Curing and Port Removal

The injected material is allowed to cure fully before port removal. Polyurethane foam typically achieves initial cure within 15 to 30 minutes; full cure occurs within several hours. Epoxy systems require 24 hours for full cure. After curing, surface ports are snapped off flush with the wall and the surface cap is smoothed. The completed repair is inspected for any areas of incomplete fill.

Crack injection is one of those repairs where doing it right the first time costs far less than doing it twice. The material has to reach through the full depth of the wall to be effective. We will not cut corners on port spacing or injection pressure.
DV
Derek Veselich
Owner, Ground Up Foundation Repair

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Installing an exterior French drain system with perforated pipe.

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Your gutters collect a surprising amount of water during a Middle Tennessee rainstorm, a typical roof can shed hundreds of gallons per inch of rainfall. When downspouts discharge that volume at the base of your foundation, the surrounding soil becomes saturated quickly, creating the hydrostatic pressure, the force that saturated soil places against your basement wall, that drives basement moisture and flooding. Ground Up Foundation Repair installs downspout extensions, including surface extensions, flexible rollout models, and underground piped discharge systems, to move roof runoff well away from your structure before it can become a basement problem.

Exterior Waterproofing Membranes

Exterior waterproofing membranes are applied directly to the outer face of the foundation wall after excavation exposes the wall from footing to grade. The membrane forms a continuous moisture barrier across the entire exterior wall surface, sealing cracks and preventing water under hydrostatic pressure, the force that saturated soil exerts as it presses against the wall from outside, from migrating through the concrete. When combined with a foundation drainage board and footing-level drain tile, exterior waterproofing provides the most complete protection available for a basement. Ground Up Foundation Repair installs exterior waterproofing as a standalone system and as part of combined interior-exterior waterproofing packages for severe water intrusion situations.

French Drain Installation

French drains are subsurface drainage systems that intercept and redirect groundwater, surface runoff, and laterally migrating soil moisture away from a foundation or problem area. A trench filled with clean stone and a perforated drain pipe captures water moving through the soil and carries it by gravity to a safe discharge point. Ground Up Foundation Repair installs French drains as perimeter foundation drains, yard drainage solutions, and hillside intercept drains for Middle Tennessee properties where groundwater movement or surface drainage is contributing to basement moisture, yard flooding, or saturated soil conditions.

Grading & Yard Sloping

The ground immediately surrounding your home should slope away from the foundation at a minimum grade of 6 inches over the first 10 feet. When that slope is flat, reversed, or has settled unevenly over time, rainwater and snowmelt drain toward your basement instead of away from it. Ground Up Foundation Repair corrects improper yard grading across Middle Tennessee by adding and reshaping soil to establish the right slope profile, one of the most cost-effective steps a homeowner can take to prevent basement moisture problems.

Interior Drainage Systems

An interior basement drainage system is the most reliable long-term solution for chronic basement water intrusion in Middle Tennessee homes. Rather than attempting to stop water at the exterior, an interior system accepts that some water will reach the foundation and channels it away harmlessly before it can cause damage. Ground Up Foundation Repair installs complete interior drainage systems including perimeter channels, sump basins, and primary and battery backup pumps sized to handle the water volumes common during Middle Tennessee storm events.

Vapor Barriers

Basement vapor barriers are heavy-duty polyethylene or reinforced sheeting systems installed on foundation walls and floors to prevent moisture vapor from migrating through concrete into the living space. In Middle Tennessee's humid climate, unsaturated concrete walls and floors can transmit significant moisture even when no active seepage is present, enough to sustain mold growth, warp wood, and keep relative humidity at damaging levels. Ground Up Foundation Repair installs vapor barriers as standalone moisture control systems or as part of a complete interior drainage and waterproofing package.

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