We use SP-3 Proprietary Water Activated Polyurethane to stop Basement Leaks


  • SP-3 is a single-component water activated resin, injected in one application with no added activator. This one-step process ensures an appropriate blend of polyurethane-based waterproofing material on every job.
  • Once injected under high pressure, SP-3 fills the openings all the way to the outside of the foundation.
  • SP-3 reacts within 40 seconds creating a lasting bond that is pliable and elastic
  • Why does Mr. Sponge Waterproofing, Inc. have proprietary polyurethane? Because with the amount of leaks we service and warranty, we want to ensure that we have polyurethane that performs to our high specifications and will not fail. With our own polyurethane and our owner operated service, we provide the highest control and application possible in leak prevention services.




  • Epoxy injections started in the industry around the 1980's. The technique utilizes a "jake gun", or hand held caulking gun to push epoxy through the wall crack. In our opinion there are many reasons why epoxy injections fail.
  • Epoxy is injected with the hand held "jake gun" which can only produce around 90 p.s.i.
  • Epoxy's are very thick. This "jake-gun" injection system cannot deliver the material all the way through the crack which is an average 10 to 12 inch depth.
  • Epoxy cures very hard and is also susceptible to opening between the seal and the concrete surface when there is any movement or hydration of the concrete. It will not adhere or react to wet surfaces.
  • Polyurethane injections are applied with high pressure pumps that deliver an average injection pressure of 1200 p.s.i. This pressure along with our SP-3 polyurethane will travel through the depth of the wall to the outside (soil side).
  • Unlike epoxy, our SP-3 has very low viscosity, which allows maximum travel throughout the foundation wall crack and saturation to the exterior.
  • SP-3 cures very pliable unlike epoxy which is hard and brittle. This pliability allows for shifting and hydration.
  • SP-3 adapts well to wet conditions long term since it is water activated.
  • High pressure injection waterproofing is dependent on the service tech. At Mr. Sponge Waterproofing, the owners apply all in-field waterproofing services.
  • We have experience starting back in 1967 with interior waterproofing, with our owners having certified builders license in the State of Michigan.

The photographs below are examples of (Failed) epoxy injections that were hired by the builder of this condominium. These were done three years prior to Mr. Sponge Waterproofing being hired to inject with polyurethane. These show complete epoxy injection failure.