PU Injection Grouting Singapore

PU Injection Grouting in Singapore (also known as polyurethane injection grouting or PU grouting) is a leading non-hacking waterproofing technique widely used to permanently seal cracks, joints, voids, and active water leaks in concrete structures. It’s especially popular in Singapore’s humid, rainy tropical climate for addressing issues in HDB flats, condos, landed homes, basements, bathrooms, rooftops, balconies, ceilings, and commercial buildings—preventing ceiling stains, mold, structural weakening, and costly damage without major demolition.

This method injects a low-viscosity polyurethane resin under pressure into leaks; the resin reacts with water, expands (foams), and hardens into a flexible, watertight seal that bonds strongly to concrete.

Common Applications in Singapore

• Sealing hairline to wide cracks in concrete walls, floors, slabs, and ceilings.
• Stopping active/gushing leaks (e.g., during heavy rain or from roof/ceiling seepage).
• Waterproofing basements, retaining walls, bathrooms, and wet areas.
• Repairing voids/honeycombs in concrete or behind walls.
• Curtain grouting (creating a barrier in soil behind walls for below-grade leaks).
• Roof slab, balcony, and podium waterproofing without hacking.
• Structural strengthening by filling voids and preventing further water ingress.

Key Features of PU Injection Grouting

• Expanding & Flexible Seal — Resin expands up to 20–30x on contact with water, filling irregular cracks/voids completely; remains elastic to accommodate building movement, thermal expansion, and Singapore’s heat cycles.
• High Pressure Injection — Uses mechanical packers and pumps (low-pressure 20–40 psi for sensitive areas; high-pressure for deeper/stronger seals).
• Non-Hacking/Non-Invasive — Minimal drilling of small holes (often from underside/negative side); no major demolition, dust, or debris.
• Fast-Acting & Quick Curing — Stops active leaks almost immediately; full cure in hours to days, allowing same-day or next-day use.
• Low Viscosity — Penetrates deep into fine cracks (even hairline) for thorough filling.
• Durable & Long-Lasting — Resistant to UV, chemicals, alkaline cleaners, fuels; withstands Singapore’s heavy rain, humidity, and temperature fluctuations.
• Water-Reactive — Ideal for wet/active leaks; closed-cell foam prevents re-seepage.
• Eco & Low-Disruption Options — Many use low-VOC, non-toxic resins; minimal mess and downtime.

Benefits of PU Injection Grouting

• Cost-Effective — Lower labor/material costs than hacking/re-roofing; faster completion reduces overall expenses.
• Minimal Disruption — No need to vacate premises long-term; quick repairs suit occupied homes/condos.
• Permanent Solution — Forms strong, flexible bond; prevents recurring leaks and mold.
• Versatile — Works on positive/negative side, wet/dry cracks, above/below grade, and underwater.
• Structural Integrity — Restores strength by filling voids; reduces risk of further cracking or damage.
• Energy & Maintenance Savings — Better sealing reduces moisture ingress, lowering mold/repair needs and improving indoor comfort.
• Superior to Traditional Methods — Outperforms hacking (messy, destructive) or surface coatings (less penetrating) for active leaks.

Typical PU Injection Grouting Process

1. Site Inspection & Diagnosis — Free assessment, often with thermal imaging/moisture meters to locate exact leak sources.
2. Surface Preparation — Clean area, mark cracks, drill small injection holes (packers installed).
3. Injection — Low/high-pressure pumping of PU resin (from bottom-up to ensure full filling); resin expands/seals on contact with water.
4. Curing & Testing — Allow curing; flood/water test to verify no leaks.
5. Hole Repair & Cleanup — Patch injection holes, restore surface; final inspection.
6. Warranty & Handover — Documentation with 5–10+ year warranties (common from reputable firms).

Popular specialists in Singapore include:

• SWC Construction (top-rated for PU grouting, non-hacking expertise).
• Le Fong Business Services (pressure injection, long warranties).
• Adcos Asia (PU foam systems, 30+ years experience).
• DryProof Waterproofing (ceiling/roof focus).
• Proseal, Proof-Tech, Greenflex (premium materials/specialists).
• Zaman Group, Prima Seal, and others (BCA-registered options).

Many are BCA-approved and handle HDB/condo approvals.