By The Address desk · Last verified 12 October 2026
In an HDB flat, you may replace bathroom floor and wall finishes only after the first three years from the block’s completion date, and you need an HDB permit to do it. All works must be done by a contractor from HDB’s Directory of Renovation Contractors (DRC). When a bathroom floor is redone, HDB requires pre-packed waterproofing screed and a waterproofing membrane, turned up at least 150mm against walls, kerbs and pipes, with the total floor build-up kept within 50mm, followed by a water test. Breaking the rules can lead to a fine of up to $5,000. That waterproofing layer, plus hacking, curing and testing time, is why bathrooms cost more to renovate than any other room.
A bathroom is the one room where a shortcut can drip through your neighbour’s ceiling. Get the layers right once, and you will enjoy a dry, lovely bathroom for years.
Quick facts
- No removal of original bathroom floor or wall finishes in the block’s first 3 years.
- Replacing bathroom floor or wall finishes needs an HDB permit.
- Use only contractors listed in HDB’s DRC, even for works that need no permit.
- New floors: waterproofing screed + membrane, membrane upturned 150mm minimum.
- Floor finishes plus screed: 50mm maximum; wall finishes including plaster: 25mm maximum.
- Offences can bring a fine of up to $5,000, and HDB can order the flat reinstated.
The HDB rules for bathroom works
| Work | Permit? | Key conditions |
|---|---|---|
| Replace bathroom floor finishes | Yes, after 3 years | Pre-packed waterproofing screed and membrane; membrane upturned at least 150mm against walls, kerbs and pipes; total thickness within 50mm; UPVC floor trap grating with a long collar |
| Replace bathroom wall finishes | Yes, after 3 years | Do not tamper with structure; total thickness including plaster within 25mm; pre-packed plaster |
| Enlarge the bathroom | Yes, after 3 years | Up to 600mm wide and 0.6m²; dry area only; gas riser and branch pipe must not be enclosed |
| Top up floor with lightweight screed | Yes | Remove existing finish and screed first; loading within 120kg/m²; waterproofing screed and membrane |
| Replace kitchen floor finishes | Yes | Within 50mm; waterproofing screed; membrane with 150mm upturn around sanitary stacks within a 400mm radius |
These are HDB’s guidelines as of October 2026. Approval comes as a permit, issued before the works start, and HDB holds you, the owner, responsible for making sure your contractor follows the rules. Confirm with your contractor who is submitting the permit application before any hacking begins.
How a waterproofed bathroom floor is built
- Hack the old tiles and screed, and clear the debris.
- Prepare the base and check the floor traps and pipe sleeves.
- Lay the pre-packed waterproofing screed and the waterproofing membrane, as HDB requires, with the membrane turned up at least 150mm against walls, kerbs and around pipes. Your contractor should explain the sequence and product used.
- Run the water test, which HDB requires after floor finishes are replaced, to show nothing seeps through.
- Tile and fit the UPVC floor trap grating with a long collar, keeping the total build-up within 50mm.
Ask your contractor to photograph the membrane and the water test before the tiles go on. Once tiled, you can no longer see the layer that matters most.
Why bathrooms cost more than other rooms
- More layers: hacking, membrane, waterproofing screed and tiles, rather than tiles alone.
- More trades: tiling, plumbing, electrical works and carpentry for vanities, often each scheduled separately.
- Waiting time: the water test, and time for materials to set, stretch the job across more days.
- Fittings: water closets, basins, taps and heaters add up quickly.
- Risk: a mistake means hacking up new tiles, so careful contractors price that care in.
Prices vary widely by flat size and materials, so collect itemised quotations from two or three DRC contractors and check that each one names the membrane and the water test as separate line items.
The WahLiao Verdict
If your bathroom is still within the block’s first three years, enjoy it as it is; the rules do not allow full replacement yet. When the time comes, never accept a quotation that skips the membrane or the water test to save money, and only hire from HDB’s DRC list. The waterproofing is invisible, but it is the part of the bill that protects both your home and the family living below you.
Questions people ask
Can I hack my BTO bathroom tiles straight after collecting keys?
No. HDB bars removal of the original bathroom wall and floor finishes for three years from the block’s completion date.
Do I need a permit to retile my bathroom?
Yes. Replacing bathroom floor or wall finishes after the three-year period needs an HDB permit, and the work must be done by a DRC contractor.
Who pays if my new bathroom leaks into the flat below?
As the owner, you are responsible for your renovation, so expect to fix the leak. Check your contractor’s workmanship warranty and keep the photos and water test record.
What happens if I use a contractor not on the DRC list?
It is an offence that can lead to a fine of up to $5,000 on conviction. HDB can also revoke permits and require the flat to be reinstated.
Sources: HDB, renovation guidelines for building works; HDB, important information on renovation, DRC contractors and penalties. The Address explains; it does not advise.
Read next: HDB Renovation Rules: Permitted Hours, Noisy Works and Permits · Ceiling Leaks and Water Seepage in HDB Flats: Who Pays to Fix Them · Back to The Address
For what’s worth it this week, with the bill shown, read The WahLiao Week.
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