Selection reference
Choose the crack repair material by crack condition
A crack is a symptom. Identify whether it is dormant or moving, structural or cosmetic, dry or leaking, and how soon the area must return to service, then pick the material and packaging that fit that condition and the crack footage.
| Crack condition or repair method | What to confirm |
|---|---|
| Structural cracks, pressure injection in bulk units | Dormant cracks in walls, beams, columns, slabs and foundations that must be bonded back to full section. Confirm the ASTM C881 type, grade and class named in the specification, then match viscosity to the crack width: the tighter the crack, the lower the viscosity needed to travel its full depth. High-modulus resins suit rigid structural members; choose a low-modulus resin where the member sees shock or vibration. Check moisture tolerance against the actual substrate, pot life against the crew and pump you have, and the unit size against the total footage. Gallon and multi-gallon units such as Sikadur 35 Hi-Mod LV, Sikadur 52 and Dural 452 LV assume metering or batch-mixing equipment rather than a hand gun. |
| Limited footage, cartridge injection | Port injection or gravity feed of a few cracks with a dual-cartridge gun and static mixer. Confirm the published footage per cartridge or kit at a stated crack width, whether ports, capping paste and mixers are included, the minimum crack width the resin will penetrate and the cure time at the job temperature rather than at 73°F. Kits such as the Sikadur Crack Repair Kit package the full sequence for short runs; individual cartridges let you pick the resin, for example a high-modulus resin for most cracks or a low-modulus, extremely low-viscosity resin such as Prime Rez 1200 for hairline cracks and members under vibration. Confirm the gun ratio matches the cartridge. |
| Capping, port setting and small vertical repairs | A non-sag epoxy gel seals the crack face and bonds injection ports before pressure injection, and also patches small spalls overhead or on walls. Confirm the gel’s cure time before injection can begin, its working time at the ambient temperature and its compatibility with the injection resin so the cap holds under pressure. Bulk gels such as Sikadur Injection Gel suit long capping runs; a cartridge gel such as Miraclebond 1310 is faster for a handful of ports and small repairs. Plan how the cap will be removed or ground flush after the injection cures. |
| Floor cracks and spalls, fast return to service | Industrial floors, warehouses, docks and freezers where downtime is the real cost. Ultra-low-viscosity hybrid urethane and polyurea liquids penetrate the crack and can be sand-extended into a mortar for spalls and pop-outs. Confirm foot and heavy-traffic times, the low-temperature limit for freezer or winter work, the allowed aggregate ratio and lift thickness, and color options if appearance matters. These products set in minutes, so confirm the mix-and-place window and crew size before opening a bulk unit; cartridges such as Quick Mender XO or Euco QWIKstitch units suit spot work. The surface must be clean and dry; these are not injection resins for structural cracks. |
| Leaking or actively wet cracks | Water infiltration through walls, slabs or joints is stopped with hydrophobic polyurethane foam that reacts with the water, not with rigid epoxy that the water displaces. Confirm the water flow and pressure, the crack width, whether packers or surface ports will be used, foam expansion and set time, and the cartridge or pump method the product is packaged for. A cartridge foam such as Prime Flex 985 covers spot leaks; larger or higher-flow leaks move to pumped urethane grouts. Decide up front whether a structural epoxy injection follows once the crack is dry. |
Moving cracks, control joints and expansion joints are not candidates for rigid epoxy injection; see joint fillers. Published viscosity, strength and cure values apply only at the stated temperature and mix ratio; use the current product datasheet before approving a substitution.
Field planning
Plan the concrete crack repair
Durable crack repair depends on reading the crack correctly, preparing it thoroughly and placing the material within its working time. Use the manufacturer datasheet with the project specification and any engineer’s direction.
Diagnose before you inject
Measure crack width and depth, look for movement across seasons or loads, and check for moisture, efflorescence or corrosion staining. A crack that is still moving or still leaking will reopen if it is filled with a rigid material before the cause is addressed.
Structural repairs follow the engineer’s direction and the ACI and ICRI crack repair guides. Cosmetic and floor repairs still need the cause identified, or the repair becomes a maintenance cycle.
Clean, seal and port the crack
Remove dirt, laitance, oil and loose material with a wire brush, saw or grinder, then vacuum and blow out with oil-free air. Most epoxies tolerate damp concrete but not standing water; hybrid urethane floor products require a dry surface.
For pressure injection, cap the crack face with a non-sag gel and set ports at a spacing roughly equal to the member thickness. Horizontal hairline cracks can be routed to a shallow V-groove for gravity feed.
Inject or place within the working time
Start at the lowest or widest port and move to the next as resin appears there. Keep pressure low and steady; slow travel into a tight crack is normal for low-viscosity resins. Cartridge systems need the gun, static mixer and needle tips matched to the product.
Bulk units require metering equipment and a crew sized to the pot life. Condition material to the datasheet temperature range; cold resin thickens and warm resin gels early.
Return to service and finish
Hybrid urethane and polyurea floor repairs typically take foot traffic in minutes and heavy traffic within about an hour; epoxy injection resins cure over hours to days and reach design strength later. Read the datasheet for the job temperature, not the ideal case.
Shave or grind excess flush after set, remove ports and capping if required, and color-match floor repairs where appearance matters. Record product, batch, footage and conditions for the closeout.
Before you order
Concrete crack repair specifications & quantity planning
Use the specification and the selected manufacturer data to confirm the performance, quantity and accessories the repair requires.
Compare the specified performance
Check the ASTM C881 type, grade and class, viscosity, modulus, bond and compressive strength, moisture tolerance, minimum application temperature and pot life. Floor repair liquids are compared on traffic time, low-temperature limit and hardness instead.
Calculate resin and cartridges
Estimate crack volume from length, average width and depth, then add an allowance for voids behind the crack and mixer waste. Divide by the yield of the exact cartridge or unit and round up. For spalls, include the sand ratio the datasheet allows.
Assemble the tools and submittal
Confirm the dispensing gun, static mixers, needle tips, ports and capping paste for the chosen system, plus PPE and cleaning solvent. Gather the current product datasheet, SDS and any compliance documents the project requests.
Project orders
Request concrete crack repair project pricing
Send the specified crack repair products and quantities for your repair, shutdown or floor maintenance program. If the product is still under review, describe the cracks and the structure and we will help match a system.
Include with your request
- Crack type: structural, floor or spall, or leaking
- Total footage with typical width and depth
- Structure, moisture condition and required return to service
- Delivery ZIP and required-on-site date
Concrete crack repair questions
What is the best product for repairing cracks in concrete?
It depends on the crack. Dormant structural cracks are pressure-injected with low-viscosity epoxy. Floor cracks and spalls that must carry traffic quickly use rapid-setting hybrid urethane or polyurea liquids. Leaking cracks are sealed with hydrophobic polyurethane foam. Moving cracks and joints need a flexible joint filler, not a rigid repair.
What is epoxy crack injection?
The crack face is capped with a non-sag epoxy gel, injection ports are bonded along the crack, and a low-viscosity two-component epoxy is pumped or gun-injected from port to port until the crack is filled. The cured epoxy bonds the concrete back together and restores load transfer across the crack.
Can epoxy be injected into a wet or leaking crack?
Many injection epoxies tolerate damp concrete, but flowing water prevents bond and displaces the resin. Stop active leaks first with a hydrophobic polyurethane foam such as Prime Flex 985, then inject epoxy once the crack is dry if a structural repair is still required.
How much crack can one cartridge or kit repair?
Yield depends on crack width and depth. Manufacturers publish approximate footage per cartridge or kit at a stated width; the Sikadur Crack Repair Kit and Prime Rez cartridges each list theirs on the datasheet. Estimate volume from your measurements and round up, because resin also fills voids behind the crack.
How soon can a repaired floor take traffic?
Rapid-setting products such as Euco QWIKstitch and Versaflex Quick Mender XO are published for heavy traffic in about an hour at normal temperatures. Epoxy injection resins cure over hours and reach design strength over days. Cold temperatures extend every cure time; check the datasheet at the actual job temperature.
Do hairline cracks need to be routed before repair?
Not for pressure injection; an extremely low-viscosity resin is chosen to reach the tight crack instead. Routing a shallow V-groove is common for gravity-fed repairs on horizontal surfaces and for floor repair liquids, because the groove gives the material a reservoir and a clean bond surface.
Please complete your information below to login.