Technical tips FAQ for Concrete Crack Injection & Repair.

The cost can vary depending on the type of crack repair. If it is structural or if it is leaking. An excellent example would be a poured concrete basement wall that has cracked diagonally down from a window to the floor 6 ft long, a non-structural crack. Using a standard polyurethane product would be an excellent choice. A polyurethane kit would cost $140 to $215, depending on the size of the kit purchased. You save on the labor cost if you are buying a DIY kit. This same crack repaired by an experienced foundation contractor may range from $400 to $800 depending on your location, the level of expertise, and any other costs built into this repair such as overhead, warranty, labor, and worker compensation costs. There is no average per ft price by contractors, but the cost could be five times the material costs. If you take this ratio into account when you are adding up the costs, there can be significant savings by doing the work yourself or considering this work as an added service if you are a contractor.

Yes, doing crack foundation injections in the winter can be accomplished by allowing the basement wall exposure to the building's heat by removing any insulation against the wall. It will require 3 or 4 days for the concrete to warm to at least 40°F. In extremely cold outside temperatures, you may need to insulate the exterior wall temporarily.

Low Pressure: 1) Wire brush the concrete surface. 2) Dry the wall if wet. 3) Attach injection ports. 4) Use epoxy seal paste to seal the crack between/around ports. 5) Inject Epoxy or Polyurethane. 6) After cure, remove ports if necessary.

High Pressure: 1) Drill locations for injection packers. 2) Clean out drill holes and install packers. 3) Inject polyurethane using a pump or modified grease gun. 4) Leave packers in place for 1 week and then remove zerk tips if they are in the way.

Attaching standard surface ports to a wet wall is difficult. Option 1: drill a 5/8" hole ~1" deep, hammer in corner ports, seal with Blitz powder or hydraulic cement, then proceed with low-pressure injection (epoxy or polyurethane). Option 2: high-pressure polyurethane injection using packers with a modified grease gun or pump—no special drying prep needed.

Use Epoxy for structural cracks (e.g., horizontal, > 1/4" wide) or when structural bonding is required. For narrower, mostly vertical, leaking cracks (common from windows), Polyurethane is an economical choice that permanently stops water.

No. NextStar epoxies span viscosities from ultra-low (#4 ULV for hairline cracks, slow 4-day cure) to very thick (101 Epoxy Injection Paste for wide cracks). LV/MV/EHV are designed to gel in 20–40 minutes to prevent drain-out and set in 24 hrs at 32°F. Products are compatible if switching viscosities during the same repair.

121 Epoxies cure at 32°F, gel 20–60 minutes, initial cure ~24 hrs. E101 Paste stops flowing when pressure stops and cures in ~24 hrs. #4 ULV is slow: gel 1–8 hrs and up to a week for full cure depending on concrete temperature.

Generally one year if not frozen. Exception: Koster 2IN1 is age-limited and should be applied within six months.

A structural crack is often considered anything larger than ¼" or any width that is horizontal. Other factors include settling, lateral force, soil erosion, low-quality concrete, damage, fire, etc. When in doubt, consult a structural engineer.

Snap ties hold forms during the pour; after forms are removed, metal remains in the wall and can rust and leak. Best repair is ultra-low viscosity epoxy to encapsulate the tie permanently (e.g., #4 ULV with an autoinjector). Hydraulic cement, tar, or polyurethane are not recommended as permanent fixes.

Injection is an approved waterproofing repair for poured concrete. For hollow block walls, injection is not recommended—the resin will migrate into cavities without sealing. Best long-term fix: exterior excavation and membrane; bowed walls may need interior carbon fiber reinforcement. Interior drains can trap water in hollow cells in frost climates and worsen damage.

Carbon fiber is stronger than steel for its weight and will not rust. Common uses: straps/grids to reinforce bowed walls, and staples/stitches for floor or wall cracks. Because carbon has no compression strength, epoxy crack injection is recommended to prevent crushing the fiber.

Perforated pipe installed around the basement just below footing level, draining into a sump pit (pumped out) or into sewer/septic on some older buildings. It relieves groundwater around the structure.

Comprehensive, professional-grade selection tailored to many foundation problems—not one-size-fits-all. Our inventory turns quickly so epoxies/polyurethanes are fresh (limited shelf life). Beyond products, we operate with full-time technicians locally and provide expert advice most competitors cannot.

No problem. Contact NextStar at 866-445-3984 (press 1 for sales) and we will email you a copy of the instructions for your kit or product.