PU Injection Waterproofing Specialist · Islandwide Singapore
PU Injection Waterproofing Singapore
NexFix Engineering seals active leaks, hairline cracks and joint failures with polyurethane resin injection. No hacking, no removed tiles, and a repair that holds up under Singapore's rain.
A PU Injection Waterproofing Repair Team That Works Around Your Home
PU injection only works when the operator drills the right angle, uses the right pressure and reads the crack correctly. We treat it as a precision repair, not a quick patch.
Precision Injection, Not Guesswork
We trace the leak path before drilling, so resin fills the actual crack instead of spreading through unrelated voids.
HDB & Condo MCST Aware
We know which floors need Town Council or MCST sign-off and prepare the paperwork so your repair clears approval fast.
No Hacking Required
Injection points use small drilled holes, not removed tiles or broken screed, so your finished surface stays intact.
Transparent, Itemised Quotes
You receive a clear price after inspection, covering the number of injection points and material used, with no surprise add-ons.
Same-Week Response
Active leaks worsen fast. We prioritise urgent PU injection repair jobs and can usually inspect within days.
1-Year Workmanship Warranty
If the sealed crack reopens or the leak returns within the warranty period, we return and fix it at no charge.
What Is PU Injection Waterproofing?
PU injection waterproofing uses a hydrophobic polyurethane resin pumped directly into a crack, joint or void under pressure. Once the resin meets water inside the concrete, it reacts, expands and turns into a dense closed cell foam that blocks the path water was using to get through.
The expansion is the part that makes it effective on hairline cracks a membrane can't reach. Liquid polyurethane travels into gaps too fine to see, then swells to many times its original volume as it cures, sealing the void from the inside rather than covering it from the outside.
Contractors use this method most on active leaks, meaning water is coming through right now, at points a general re-waterproofing job would miss: construction joints, cold joints, pipe penetrations, honeycombed concrete and structural cracks in slabs, walls and ceilings.
PU injection works on the crack itself. It doesn't replace a full membrane system if the surrounding surface has failed everywhere, which is why we always inspect first and tell you honestly if injection alone will solve your leak or if you need a broader repair.
PU Injection Specs We Work To
Signs You Need PU Injection Waterproofing Repair
These patterns tell us injection is the right fix before we even inspect. If two or more apply to your leak, book a check.
An Active, Visible Leak
Water drips or seeps right now, especially after rain, rather than showing only as an old dried stain.
A Hairline Crack With Moisture Around It
A fine crack in a slab, beam or wall that stays damp or grows a white mineral trail is actively carrying water.
A Leak At a Cold Joint or Expansion Joint
Leaks along the seam where two concrete pours meet are a textbook case for injection.
Leaking Around a Pipe Penetration
Water tracking along a pipe where it passes through a slab or wall usually means the surrounding seal has failed.
The Stain Returns After Repainting
Repainting hides a stain but never seals the source, so it reappears within weeks if the crack is still open.
You Want To Avoid Hacking Tiles
If the leak source is a crack rather than a failed membrane across the whole floor, injection can fix it without removing finishes.
Where We Apply PU Injection Waterproofing
Any concrete structure with a crack, joint or void carrying water is a candidate for injection.
Ceiling Cracks
Slab cracks leaking into the unit below
Wall Cracks
Structural or shrinkage cracks in walls
Cold & Expansion Joints
Seams between concrete pours
Pipe Penetrations
Gaps around pipes through slabs
Basements & Retaining Walls
Below-grade cracks under water pressure
Roof Slabs
Structural cracks under roof membranes
Balconies & Terraces
Slab cracks at floor level
Water Tanks & Sumps
Joint and wall leaks under constant pressure
Our PU Injection Waterproofing Process
A controlled sequence that seals the crack correctly the first time, instead of masking a symptom.
Leak Tracing & Free Inspection
We follow the water back from the visible stain to the actual crack or joint causing it, and confirm injection is the right method.
Mark Injection Points
We map drill points along the crack path so the resin reaches every section carrying water, not just the visible end.
Drill & Install Injection Packers
Holes are drilled at roughly 45 degrees to intersect the crack, then fitted with packers that hold the injection nozzle in place.
Pressure Injection
Polyurethane resin is pumped through each packer at a pressure matched to the crack size, until resin surfaces at the next point.
Expansion & Cure
The resin reacts with moisture in the crack, expands to fill the void and cures into a flexible, water-blocking seal within minutes to hours.
Test, Patch & Handover
We check the area under water or rain simulation, remove the packers, patch the drill holes flush, and walk you through the completed repair.
PU Injection vs Hacking & Re-Screeding
Both fix leaks. They solve different problems, and picking the wrong one wastes your time and budget.
PU Injection Waterproofing
- Targets a specific crack, joint or void carrying water
- Small drilled holes only, tiles and screed stay intact
- Usually completed in a single visit
- Minimal noise, dust and disruption to neighbours
- Best when the leak source is localised, not spread across the whole floor
Hacking & Re-Screeding
- Removes the entire floor finish down to the slab
- Replaces the whole waterproofing membrane, not just one crack
- Takes several days, often with drying time between layers
- Heavier noise and dust, more disruptive to daily use
- Right choice when the membrane has failed across the whole area, not just at one point
We recommend hacking only when injection genuinely won't hold, and we'll tell you plainly which one your leak needs after inspection.
Why Polyurethane Resin Holds Up
Not every sealant belongs in a crack that faces constant water pressure and building movement. Polyurethane earns its place here.
Fast Curing
The resin reacts on contact with moisture and cures quickly, which suits active leaks that need sealing before water spreads further.
Low Viscosity
Its thin, fluid state lets it travel into hairline cracks a thicker sealant or membrane can't reach.
Stays Flexible After Curing
Unlike a rigid patch, cured polyurethane keeps some flex, so it moves with the concrete instead of cracking again under thermal expansion.
Resists Water Pressure
The expanded foam forms a dense seal that holds against hydrostatic pressure in basements and below-grade walls.
Handles UV & Weather Exposure
On roof slabs and balconies, cured resin resists degradation from sun exposure better than untreated patch materials.
Low Maintenance After Application
Once sealed and tested, an injected crack needs no ongoing upkeep beyond your normal building maintenance.
PU Injection Waterproofing Cost in Singapore
Indicative starting prices below. Your final quote depends on the number of injection points, crack length and access difficulty.
| Scope | Starting From |
|---|---|
| Single Crack, 1 to 2 Injection Points | From S$280 |
| Ceiling Leak, Slab Crack Injection | From S$380 |
| Cold Joint / Expansion Joint Repair | From S$420 |
| Pipe Penetration Seal | From S$320 |
| Basement / Retaining Wall Injection | Custom Quote |
| Multiple Points, Same Visit | Bundled Discount |
Prices are indicative and exclude GST. Book a free inspection for an accurate, itemised quote before any work starts.
How Long Does PU Injection Waterproofing Take?
Most PU injection repairs finish in a single visit, far faster than a full re-waterproofing job.
Single crack or joint, one visit
Multiple injection points in one unit
Ceiling leak with access setup required
Basement, large slab or commercial scope
What Clients Say About Our PU Injection Repairs
Feedback from recent PU injection waterproofing jobs across Singapore.
"Our ceiling leaked every time it rained. NexFix traced it to a hairline crack in the slab above and sealed it with PU injection in under two hours. No hacking, no mess."
"They were upfront that our issue needed injection, not a full re-waterproofing job, which saved us a lot of money and disruption. Leak hasn't returned."
"Basement wall was seeping along a joint after heavy rain. Team injected the joint and pressure tested it before leaving. Dry ever since."
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Frequently Asked Questions
What does a PU injection waterproofing specialist actually fix?
A specialist targets active leaks coming from a specific crack, joint or void in concrete, sealing that exact path rather than treating the whole surface.
Does PU injection waterproofing repair require hacking tiles?
No. Injection uses small drilled holes to reach the crack, so tiles, screed and existing finishes stay intact throughout the repair.
How fast does the leak stop after PU injection?
The resin reacts and expands on contact with moisture, often sealing the crack within minutes, with full cure completing within a few hours.
Is PU injection waterproofing service suitable for HDB and condo ceiling leaks?
Yes, when the leak traces back to a crack or joint in the slab above. It's often the fastest fix and avoids disputes over hacking work in the unit above.
Can PU injection handle a leak under constant water pressure, like a basement wall?
Yes. Once cured, the resin resists hydrostatic pressure, which makes it a common choice for basement and retaining wall leaks.
When should I choose hacking instead of PU injection?
If the membrane has failed across the entire floor rather than at one crack, hacking and re-screeding gives a more complete fix. We tell you honestly which one your case needs.
Do you offer a warranty on PU injection waterproofing repair?
Yes, every job comes with a 1-year workmanship warranty. If the sealed crack reopens or the leak returns, we return and fix it at no charge.
Why NexFix Engineering for PU Injection Waterproofing
A specialist team that treats every crack as a diagnosis, not a default fix.
Areas We Serve in Singapore
Islandwide PU injection waterproofing coverage, with technicians regularly working across every region.
Got an Active Leak? Stop It at the Source.
Book a free inspection and get an honest recommendation on whether PU injection or a fuller repair fits your leak.
Explore our full Waterproofing Services in Singapore → or read about Ceiling Leak Repair Singapore →