10ft DIY Polyurethane Foundation Crack Injection Kit — Auto-Injector, No Tools Required
Seal Leaking Basement Walls With No Injection Gun and No Caulk Gun — Professional Low-Pressure Results for DIYers and Contractors
Leaking poured concrete basement foundation wall cracks
Repairs non-structural leaking cracks from 1/32 to 3/16 inch wide
No injection gun and no caulk gun — the ports do the work
Low-pressure injection at 24 to 40 psi — professional results, no equipment
Expands up to 20x its volume — fills the full crack void and stops leaks
All work from the inside — no exterior digging required
The same professional-grade material we supply to contractors
Repair lasts the lifetime of the structure
Optional upgrade to 20 ft kit at checkout
Free NextStar Technical Support — 1-866-445-3984
Ships USA & Canada
No Tools Required — How Auto-Injector Ports Work
Most foundation crack kits sold online still require a tool to push the material into the wall. The popular Amazon kits ship with a dual-cartridge gun or a grease gun; the retail DIY kits tell you to supply your own caulking gun, then sell you one if you don't have it. This kit needs none of that.
The pressure mechanism is built into each surface port. Once you load the mixed polyurethane into the port, the auto-injector delivers a continuous low-pressure injection at 24 to 40 psi on its own — the same low-pressure range a professional setup targets, with no gun, no caulk gun, and no pneumatic equipment. Every tool needed for the repair is already in the box. That is what makes this the genuinely self-contained kit: load the port, and the port does the work.
Watch the installation video →
Crack Width Range — 1/32 to 3/16 Inch Wide, and Which Resin to Choose
This kit repairs leaking non-structural cracks from 1/32 to 3/16 inch wide in poured concrete. Two resin options are available so the material matches your crack:
| Your crack |
Choose |
Why |
| Leaking crack 1/32 to 3/16 inch |
Standard Polyurethane (default) |
Expands up to 20x to fill the crack and any voids behind the wall; stays flexible |
| Finer leaking crack 1/32 to 1/16 inch |
Koster 2N1 Resin (option) |
Select at checkout. Sets as a hard resin when the crack is dry, foams when water is present; aggressive reaction suited to finer cracks |
| Ultra-fine crack 1/64 inch and smaller |
Type 3 ULV Epoxy Kit → |
Ultra-low-viscosity epoxy penetrates cracks too small for polyurethane even under high pressure |
The standard polyurethane is the right choice for the most common residential foundation crack. Koster 2N1 is selectable from the options dropdown for finer 1/32 to 1/16 inch cracks — its expansion responds to the moisture present in the crack, so it reacts aggressively where water is active and sets hard where it is not. For anything finer than 1/32 inch, the Type 3 ULV Epoxy Auto-Injector Kit is the correct tool. If you need to scale up or want a professional dispensing gun for ongoing work, see the Pro Polyurethane Injection Kit (10 to 60 ft).
Kit Components — 10 ft Auto-Injector Polyurethane Kit
946 ml (2 Pints) Two-Component Polyurethane Foam:
Injects approximately 8 ft of crack at 3/16 inch wide, up to 10 ft for smaller cracks. Expands on contact with moisture to fill the full crack void, including voids behind the wall.
Epoxy Crack Seal and Port Adhesive — 2 × 300 ml (Part A & B):
Fast-setting paste for securing injection ports to the wall and sealing the crack surface between ports.
15 Surface Ports with Auto-Injectors:
The key feature of this kit. The auto-injector is built into the port, delivering continuous low-pressure injection at 24 to 40 psi with no gun or applicator. Provides the same results as professional injectors.
Accessories:
6 wooden mixing sticks, putty knife, wire brush, 3 pairs of nitrile gloves, and safety glasses.
Complete Instructions & MSDS Safety Data
The 10 ft kit can be upgraded to 20 ft at checkout — ideal for longer cracks or multiple repairs. Call 1-866-445-3984 to discuss custom quantities for contractor use.
Why Polyurethane Works for Leaking Foundation Cracks
Polyurethane foam reacts with the moisture already present in a leaking crack and expands up to 20 times its injected volume, filling not just the visible crack but any voids behind the wall face. The cured foam stays flexible, absorbing the seasonal thermal movement a concrete foundation goes through without re-cracking. Hydraulic cement and caulk only patch the visible surface and leave the interior open; full-depth polyurethane injection is what makes the repair last the life of the structure. An actively leaking crack is actually ideal — the water speeds up the foam reaction.
Installation Steps
- Put on protective gear. Put on the supplied nitrile gloves and safety glasses before handling any materials, and wear them throughout the repair.
- Clean the wall surface. Using the wire brush, clean the crack and surrounding wall back to bare concrete. Remove any paint, efflorescence, or loose material along the crack path.
- Mix the port adhesive paste. Mix a small batch of epoxy crack seal paste (Part A + B) by hand until uniform in colour.
- Attach surface injection ports. Using the mixed paste, attach surface ports along the crack every 8 to 10 inches, alternating sides where possible.
- Seal the crack surface. Apply the remaining paste over the crack between ports to seal the surface. Allow to cure until firm, approximately 1 to 2 hours.
- Prime the crack with water. Once the paste has cured, inject a small amount of water into each port from the bottom up to activate the polyurethane reaction. Skip this step if using the ULV Epoxy version.
- Mix and load the polyurethane. Mix the two-component polyurethane per the instructions and load it into the auto-injector ports, starting at the lowest port.
- Inject from the bottom up. The auto-injector generates low pressure automatically once loaded. When polyurethane reaches the next port up, load that port and continue upward until the top port is complete.
Tips & Notes
1. An 8 ft crack takes about 4 hours for a first-time DIYer — plan your day accordingly.
2. Expanding foam is messy. Lay plastic sheeting on the floor below the repair area before starting.
3. Leaking cracks inject better wet. If the crack is actively leaking, inject it as-is — the moisture speeds the reaction.
4. For pipe openings and voids, pack the port adhesive paste around the penetration first to create a seal, then inject foam to fill behind it.
5. Not the right kit? For structural cracks needing a rigid permanent repair, use the Epoxy Injection Kit. For cracks finer than 1/32 inch, use the Type 3 ULV Auto-Injector Kit.
Common Questions About Auto-Injector Polyurethane Kits
Do I need an injection gun or caulk gun for this kit?
No. Unlike the Amazon and retail kits that ship with a dispensing gun or tell you to supply your own caulking gun, the auto-injector ports have the pressure mechanism built in. Load the mixed polyurethane into the port and it injects at low pressure (24 to 40 psi) on its own. No gun, no caulk gun, no pneumatic tools — everything needed is in the box.
What crack widths does this kit repair?
Leaking non-structural cracks from 1/32 to 3/16 inch wide with the standard polyurethane. For finer cracks from 1/32 to 1/16 inch, select the Koster 2N1 resin option. For cracks finer than 1/32 inch, use the Type 3 ULV Epoxy Auto-Injector Kit, which penetrates voids polyurethane cannot reach.
What is the Koster 2N1 resin option for?
Koster 2N1 is a selectable resin for finer leaking cracks from 1/32 to 1/16 inch. Its expansion depends on how much moisture is present in the crack — it reacts aggressively where water is active and sets as a hard resin where the crack is dry. Choose it from the options dropdown when your crack is at the finer end of the range.
How much crack will one kit repair?
The 946 ml of polyurethane injects approximately 8 ft of crack at 3/16 inch wide, and up to 10 ft for smaller cracks. The kit can be upgraded to 20 ft at checkout for longer cracks or multiple repairs.
How does low-pressure auto-injection compare to a professional gun?
The auto-injector delivers 24 to 40 psi, the same low-pressure range a professional low-pressure setup targets, without the gun or equipment. For occasional or single-job repairs this gives professional results at a lower cost. For ongoing or high-volume work, the Pro Polyurethane Kit with a dispensing gun offers more control and scales to 60 ft.
Why inject polyurethane rather than using hydraulic cement or caulk?
Hydraulic cement and caulk are surface patches that seal the visible face but leave the crack interior open. Polyurethane injection fills the crack to full depth and expands up to 20x on contact with moisture, filling voids behind the wall. It stays flexible after curing, absorbing thermal movement without re-cracking. Surface patches are temporary; injection is a lifetime repair.
Will this kit work on an actively leaking crack?
Yes. An actively leaking crack is ideal for polyurethane injection because the moisture accelerates the foam reaction. The water pre-injection step can be skipped entirely when the crack is already wet.
How long will the repair last?
A properly injected polyurethane repair is designed to last the lifetime of the structure. The cured foam is flexible and durable, resisting the freeze-thaw cycles and thermal movement that re-crack a rigid surface patch.
How long does the repair take?
An 8 ft foundation crack takes about 4 hours or less for a first-time DIYer, including paste application, 1 to 2 hours of cure time, and injection. Plan the full day for the repair.
Can I use this kit for pipe openings and ceiling cracks?
Yes. For pipe penetrations, pack the epoxy paste around the pipe first to create a surface seal, then inject polyurethane behind it to fill voids. The auto-injector system works in any orientation, including overhead ceiling cracks.
Is technical support available?
Yes. Call NextStar toll-free at 1-866-445-3984 Monday to Friday, 8:30 am to 5:00 pm. Our technical team can walk you through any step of the repair.
Questions during your repair? Call our free technical support line at 1-866-445-3984 — our team is available to help throughout your project.
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