When is PU Injection needed?
PU Injection (Polyurethane High-Pressure Grouting) is suitable for the following situations:
✅ 1. Active water leakage through cracks
Continuous dripping from the ceiling
Leakage occurring after rainfall
Seepage through basement or parking garage slabs
Leakage in basements or retaining walls
This is the most common application for PU Injection.
✅ 2. Concrete cracks subject to water pressure
Examples:
Basements
Water tanks
Elevator pits
Retaining walls
Parking garage slabs
Upon contact with water, the PU material foams and expands, filling the crack and stopping the flow of water.
✅ 3. Situations where access from above is not possible
Examples:
Unable to access the unit above
Parking garage slabs
Shopping malls
Apartment units
In these cases, high-pressure grouting is typically performed by drilling holes and installing packers from the underside of the slab.
When is PU Injection alone not recommended?
❌ 1. No active leakage; only surface cracks
Consider these alternatives instead:
Crack repair
Epoxy injection (for structural cracks)
Sealant repair
❌ 2. Leakage caused by a failed waterproofing layer
Examples:
Aged roof waterproofing
Failed bathroom waterproofing
Failed balcony waterproofing
PU Injection can only stop leakage through cracks; it cannot replace a waterproofing layer. If the waterproofing layer has failed, re-waterproofing is usually required.
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