Skip to content
Seepwise

PU Injection Waterproofing in Singapore

Seal the crack the water travels through, without hacking the floor. Good for the right leak, wrong for a failed membrane.

Injection ports Resin fills the path the water used Does not replace a failed membrane

Last updated: 2026-10-10

Seepwise arranges PU injection waterproofing in Singapore: a non-hacking repair where polyurethane resin is pumped into the cracks and joints a leak travels through. It avoids the noise, dust and permit of hacking, and it suits some leaks well and others not at all.

What happens on the first visit

The specialist confirms the leak path first, because injection only works if the water is travelling through cracks or joints that can be reached and filled. If the membrane under a toilet floor has failed across the whole area, injection is the wrong tool and you are told so.

How PU injection works

Small holes are drilled along the crack or joint, injection ports are fitted, and polyurethane resin is pumped in under pressure. The resin reacts with moisture, expands and fills the path the water was taking. The ports are removed and the holes sealed.

When it fits, and when it does not

SituationPU injectionRe-screeding
---------
Leak along a specific crack or jointGood fitWorks, more disruptive
Cannot hack (new BTO warranty, rental, timing)Useful stopgapNot possible yet
Want a long-term renewalPartialYes

HDB's own description of the most effective ceiling-leak fix is re-screeding (HDB). Injection is the alternative when hacking is not possible or the leak is localised.

What to ask before agreeing to injection

  • Where exactly will the ports go, and why there?
  • What happens if the leak returns: is a re-injection included?
  • Has the leak path been confirmed by a dye or ponding test?
  • Would re-screeding be the better fix here, and why not?

What is included

  • Leak path confirmed before injection
  • Ports placed along the path
  • Resin injected under pressure
  • Ports removed and holes sealed
  • Ceiling below checked after
  • Honest note if re-screeding is the better fix
  • Photos of port positions
  • Written terms if the leak returns

Painting over it vs a quick fix vs a proper repair

DIYQuick fixProper repair
HackingNoneNoneNone
Leak path confirmedNoOften notDye or ponding test first
Right method chosenGuessInjection for everythingInjection only where it fits
Return termsNoneVagueWritten
Membrane renewedNoNoNo: say so if needed

What it costs

Injection is priced by the length of crack or joint after the leak path is confirmed.

Try the cost estimator or read the waterproofing cost guide.

Related guides

How it is done

  1. Confirm the path. Dye or ponding test shows where water travels.
  2. Drill and port. Small holes along the crack or joint.
  3. Inject. PU resin fills the path under pressure.
  4. Seal and check. Ports out, holes sealed, ceiling below checked.

Get pu injection leak repair quoted after a proper inspection.

A specialist calls you back to book an inspection. Tell us what you see and the type of home.

Questions people ask

Is PU injection a permanent fix?

It can last well for a localised crack, but it does not replace a failed membrane. For a membrane failure, re-screeding is the long-term fix.

Does PU injection need an HDB permit?

Injection does not hack the floor. Hacking is what generally triggers the permit; confirm with your contractor for your flat.

Can PU injection be done in a new BTO flat?

If the flat is under warranty, report the leak to HDB first: changing tiles or the waterproofing can end the warranty.

How long does it take?

Typically far shorter than a re-screed, because nothing is hacked and no ponding test of a new membrane is needed. The specialist confirms after inspection.

Is there a charge for sending a request?

No. Sending a request costs nothing. The specialist explains any inspection fee before the visit.

Request a leak inspection