The Contractor’s Dilemma: Picking the Wrong Cure Time

You inject grout into a basement wall crack, expecting it to set in 30 seconds—but it stays runny. Meanwhile, water keeps gushing in. Or worse: It hardens too fast, clogging your injection hose before reaching the leak.

Sound familiar?

The Science Behind Cure Speed

Water-soluble PU grout comes in two lifesaving variants:

1. Fast-Set (20–90 seconds)
✔ Best for: Gushing leaks, pressurized pipes, active water flow
✔ Expansion: 10–15x (fills cracks tightly)
✔ Use Case: A burst pipe in a hospital basement

2. Slow-Set (5–20 minutes)
✔ Best for: Deep cracks, voids, or precision applications
✔ Expansion: 3–5x (controlled spread for large gaps)
✔ Use Case: A leaking underground parking garage slab

Pro Tip: The "Layered Injection" Technique

For large or deep cracks:

  1. First pass: Slow-set grout to fill the void

  2. Second pass: Fast-set grout to seal the surface

Case Study: The Bridge That Couldn’t Be Shut Down

A highway overpass leaked saltwater onto traffic below. Engineers used:

  • Slow-set grout to fill internal voids

  • Fast-set grout to seal surface cracks
    Result:

  • Zero traffic disruption

  • Leak stayed sealed for 5+ years

The Takeaway

Match the grout to the leak—or pay the price in callbacks.