Professional Equipment and Materials to Stop Leaks
The largest kit for stopping leaking foundation cracks with Hydra Stop 300 polyurethane foam. Repair the leaking basement cracks from the inside of the basement. There is no digging, drilling holes or chiseling out the crack. Hydra Stop 300 Polyurethane foam is injected into your concrete cracks. After injection the Hydra Stop 300 begins to foam and expand. It seals cracks, voids and deteriorated concrete that leak water. Poxy Paste is a low odor mercaptan based fast setting surface port and crack seal adhesive. The Spring Drive Gun gives a smooth and continuous flow of the Hydra Stop 300 into the crack. This ensures that the crack is filled entirely the length of the crack. After curing the crack will not leak water.
Application & Coverage
Suitable for application in concrete cracks 1/32” to 1/4” in width. Concrete should be above 40 F. Can be used to stop leaks in dry or wet cracks. Surface of the concrete must be dry for use.

Where to Use
- Cracks wider than 1/32″ (thickness of a fingernail)
- Concrete cracks in basement walls
- Retaining walls
- Sewers
Use from the basement interior only when repairing a basement wall crack.
Repair Process
Hydra Stop 300 is a low viscosity liquid polyurethane. Once inside the crack, the Hydra Stop begins to foam and expand. This expansion completely fills the crack and stops water.Step
1. View the video included with the kit
2. Attach surface or corner ports over the foundation crack using Poxy Paste Crack Seal & Port Adhesive
3. Cover the entire foundation crack with Poxy Paste Crack Seal & Port Adhesive
4. Inject liquid Hydra Stop 300 polyurethane crack injection resin into the foundation crack with a caulk gun
5. Place caps into the surface or corner ports to seal them
Cured Hydra Stop 300

This is an example of the fully cured Hydra Stop 300. It remains flexible and forms a closed cell structure.