Should I choose epoxy or polyurethane injection over other waterproofing methods?
Pressurized injection is used exclusively for poured concrete foundations and structures. Pressurized injection involves either epoxy or polyurethane and is used for the repair and waterproofing of cracks, holes, or cavities in foundation walls, from inside the home almost exclusively. It is a very common repair method for poured concrete waterproofing and is the least costly method of repairing active leaks and/or preventing potential leaks in poured concrete foundation walls. A professional injection will keep water from entering your basement, reduce basement dampness, and prevent moisture from permeating and damaging the poured concrete foundation walls.
Pressurized injection especially, is a waterproofing method that requires technicians to possess considerable skill, experience and tenacity. Waterproofing Contractors that do not offer pressurized injection services inevitably have realized that their organization does not possess the requisite expertise to provide reliable, long lasting injections, hence they purposely limit the waterproofing repair options they make available to you.
Note: Pressurized injection is commonly used for water-stopping in mines, subway tunnels and to seal joints between sections of concrete sewer pipes. It is also capable of withstanding extremely high levels of hydrostatic pressure, much higher than the hydrostatic pressure present around a typical foundation.
Epoxy injection involves filling a crack with epoxy, a two component chemical blend (epoxy and hardener) that binds or welds two walls together and sets as a hard plastic; in the concrete industry, epoxy injection is considered to be a structural repair.

In contrast, polyurethane injection uses an expansive resin that seals cavities and cracks by effectively forming a rubber or flexible foam gasket within the opening.
Both methods are tried and true waterproofing techniques that will solve your problem once and for all.
Note: Each type of injection has distinct technical characteristics and limitations; consequently, one size does not fit all. Rely on our technicians to determine the type of injection most suited to your particular situation.
Other available repair methods:
Traditionally, waterproofing poured concrete foundations involved the external excavation of the foundation, with the application of a concrete patch over a crack, tie-rod hole, or honeycombing in the foundation to prevent water penetration. As these patches frequently detach themselves from the wall due to incorrect application, the absence of a good chemical bond, and the natural thermal cycling that occurs on the outside of the foundation, these patch repairs fail eventually. Only the application of an elastomeric rubber coating on the outer surface of the foundation wall will reliably waterproof a foundation wall; however, excavation and waterproofing is, by far, the most expensive way to waterproof a poured concrete foundation. Furthermore, it is inherently destructive insofar as your landscaping is concerned.
Another available "broad brush" waterproofing method is internal de-watering, involving the installation of a perimeter drain tile system beneath the basement floor that captures the water that continues to leak into the basement; this method requires the use of a sump pump to mechanically pump the water to the outside. AquaGuard Injection & Waterproofing™ does not recommend this type of basement waterproofing for poured concrete foundations because water continues to enter the basement; the continuous wetting of the concrete within and around cracks and other openings will result in absorption of water and ultimately the saturation of the concrete which will weaken the concrete over time. Unlike stone, concrete is a porous material that readily absorbs water.
Yet another technique, specific to crack repair, involves the application of a rubber membrane over the leaking crack on the inside of the wall. The membrane prevents water from pooling on the basement floor as the waterchannels water beneath the basement floor slab; consequently, water continues to enter the basement and saturates the concrete surrounding the crack. The ongoing saturation of concrete will weaken the concrete over time. If the amount of water channelled beneath the floor slab is significant and there is significant hydrostatic pressure beneath the floor slab, water will enter the basement through floor cracks or through the seam between the floor slab and the wall.
Homeowners, new home builders and contractors seeking a quick fix, an inexpensive fix, or a low repair cost will often use hydraulic cement on the interior of the wall to stop a leak. Such surface repairs may stop leaks in the short term, but these repairs will cause water to be trapped within the wall; consequently, the concrete behind the repair becomes saturated with water, a condition which will lead to an accelerated deterioration of the surrounding concrete; furthermore, these types of repairs typically do not last.
The alternatives to pressurized injection are quite destructive and are certainly far more expensive than pressurized injection.
Homeowner Tip: Crack injection is a specialization that requires technicians to have considerable skill, experience and tenacity. Waterproofing contractors that do not offer pressurized injection services likely recognize that their staff do not possess the requisite expertise to provide reliable, long lasting injections; hence your available repair options are limited. This situation makes waterproofing contractor selection, on the basis of pricing alone or with limited repair options for you, a very risky proposition. For an injection to work 100% and endure the test of time it must be done properly; this is very much dependent on the skill and tenacity of the technician doing the work. It is likely impossible for you to establish whether the technician sent to your home has the requisite experience and training. If your first impression of a waterproofing contractor is less than ideal, go with your instincts; this will at least minimize the risk to you of having to call for warranty repairs at a later date and/or having to deal with poor customer service.