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Concrete Crack Injection Products General  information page

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Basic Nextstar Product Information page

 Read First Technical support is also provided during business hours at 1-866-445-3984  Extension #3 or via the contact page.

 Selecting the right kit is usually based on the size of the crack that you are dealing with and determining if it is structural or not. Most foundation cracks are not structural and can be repaired using polyurethane products, polyurethane has the advantage of expanding when it comes in contact with water filling any voids thus creating a permanent gasket. Polyurethane foams come in a few different variations so one must determine the crack size and select the proper polyurethane.

The exception for use of polyurethanes is with ultra-fine cracks that are less than 1/64 of an inch wide especially for use with low-pressure crack injection and in these cases, we use an ultra-low viscosity epoxy or Koster 2N1 polyurethane that is injected under constant pressure or gravity fed. ULV epoxy is also used to repair snap ties or wire ties that were left behind when the concrete was poured, exterior sealing over the snap ties may have failed over time allowing them to rust and allow water through. Ultra-fine foundation cracks are the most difficult types of cracks to repair and require some patience to permanently repair. The usual method would be to ULV epoxy under constant pressure over some time to allow the epoxy fill the smallest cracks and flaws, this epoxy has the advantage of being slow curing thus allowing extended injection times. Our kit 3 uses an auto-injector system that allows the epoxy to be injected under constant pressure without the applicator having to babysit the repair. Standard methods would require either a spring-loaded application tool or a pneumatic injector to accomplish this and for some cases, this may be at one-time repair, and having to purchase specialty tools may be cost prohibitive.

High-Pressure Polyurethane

100/800 foam is used for cracks that are from 1/64 of an inch to 1/32 of an inch that have been leaking and can be injected using auto-injectors or high-pressure Packers. LV polyurethane foam is a single component, these polyurethanes have an activator added just before injection and will stay active for approximately 7 days.

Standard 102 Polyurethane

foam is our standard injection product for most leaking basement walls and problems, it is true two-component polyurethane that is mixed just before injection and chemically reacts with water to that can expand over 20 times its volume size. Standard 102 can be used on cracks from just less than 1/16 of an inch to up to 3/8 of an inch wide and will be completely cured usually within a few hours but will stop the water immediately. Standard 102 polyurethane is available in several formats, one in our kit 1 auto-injector system and with our semi-pro DIY systems 10-60ft polyurethane crack injection kits. Contractors can purchase the 102 polyurethane in standard dual-tube sets.


103 Polyurethane For wider cracks

Nextstar 103 foam is our standard product for wider concrete cracks in basement or retaining walls and void fill, it is a two-component polyurethane that is mixed just before injection and does not need water to start the reaction and can expand over 20 times its volume size. Standard 103 can be used on cracks from just less than 1/8 of an inch to up to 1/2 of an inch wide and will be completely cured usually within one hour but will stop the water immediately. 103 polyurethane is available in dual cartridges 300mlx300ml
Great product for a semi-structural void fill and large nonstructural cracks. Due to it fast reaction, it is not recommended to use with feed hoses and uses a standard 1/4x 24-element mixer. 103 Polyurethane will cure as a very hard foam if the reaction is in a restricted space.


Koster 2N1 Polyurethane

foam is ideal for very fine cracks or where previous nonapproved methods have been used i.e. hydraulic cement to stop leaks. Koster 2N1 resin has the advantage of not requiring water or moisture present and will simply cure as a hard resin without moisture. The 2N1, however, may require up to 4 days to cure depending on temperature. The Koster 2N1 polyurethane can be used with high or low pressure but predicting the amount of product needed for a given crack can be unpredictable so account for 2 dual tubes per 10ft 1/8in wide. This product only has approximately 6 months of shelf life.


120 structural foam

is used to fill large voids and gaps in walls such as where pipes have been removed. This product cures very fast and requires it to be injected as quickly as possible as it expands aggressively, it will also build up a fair amount of heat in the process. 120 structural foam does not require water to be present for the chemical reaction and is typically used for cracks that are from 3/8 of an inch to 1 inch wide. Wide cracks must be also supported using carbon fiber Stitches or grid straps, structural foam cannot be crushed but has no tensile strength for holding a wall and thus the requirement for carbon fiber reinforcement. It is a good substitute for epoxy, in this case, to help reduce the cost of the repair.



Generally, epoxies are excellent products that can be used to stop leaks and effectively glue the wall or concrete back together but have the disadvantage of added cost as they do not expand during injection and in some cases product can be lost to the exterior of the wall during injection using the wrong viscosity leading to the use of more epoxy. Epoxies are required for all structural failures as the epoxy itself is much stronger than the concrete is being used to repair and has been used in the repair industry for many years. Epoxy usually requires the use of dual-component injection tools or pneumatic tools and do take a little bit more time to complete a successful repair. The use of epoxy for repair has the advantage that should the crack reopen, or the injection fails it can be re-injected. If a wall is injected with polyurethane it cannot later be injected with epoxy and may cause a problem if the original repair was a structural failure. Structural failure refers to walls that have bowed in or a crack larger than 3/8 of an inch wide and in some cases, if you are unsure, we would recommend that you have a structural engineer examine the foundation first. There may be other underlying problems with the foundation that have caused the cracking simply not bad concrete or lateral force on the wall.

Epoxy is required if carbon fiber reinforcement is used. Carbon fiber only has strength in tensile load and if a crack is allowed to compress the carbon will fail so the epoxy would prevent compression of the crack repair. Kits are sized 10ft to 60ft  

A listing and description of our polyurethane foams and epoxy products and the details of each for concrete crack repair and injection.basic review of how and when each product is used .
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