How long does a resale flat renovation take?

Resale flat renovation: the order of works

The order of works for a resale flat is: inspection, design and quotes, permit, hacking and demolition, plumbing and electrical first fix, wet works, carpentry, painting, final fix, cleaning and a defects check. Each stage depends on the one before, so an early delay pushes back the rest.

Your resale HDB renovation timeline starts before any hacking. Use the resale flat inspection checklist to note what needs repair, such as old pipes, wiring or tiles, then ask each contractor to quote on the same scope.

Plan your move-in date around the stage your contractor expects to take longest.

Permits first

Sort out the paperwork before any hacking starts. HDB says some renovations need an HDB permit, and those works must start only after the permit is granted. Works that need no permit must still follow HDB's guidelines, or they count as unauthorised works.

The application goes through your contractor. Under HDB's permit process, you authorise your DRC contractor to submit the renovation application on your behalf, using an acknowledgement form you sign.

DRC contractors know HDB's requirements, but HDB does not endorse or vouch for the quality of their works. Ask each contractor how they will handle the permit stage.

To see which works need a permit and how the process runs, read our guide to the HDB renovation permit. You can also check your plan item by item with the renovation permit checker.

Hacking and wet works

Hacking and demolition come first once the paperwork is in place. Your contractor removes old tiles, fittings, built-ins and any walls you plan to take out. Before you design a layout around removing a wall, read our guide to hacking walls in HDB flats and ask your contractor whether that wall can be hacked and whether it needs a permit.

Plumbing and electrical first fix follow hacking. New pipes and wiring routes go in before wet works, so finished tiles do not have to be broken later.

Wet works cover screeding, waterproofing and tiling. For bathrooms and toilets, HDB requires pre-packed waterproofing screed and a waterproofing membrane before new floor finishes are laid, with the membrane turned up at least 150mm against walls and kerbs. Replacing floor finishes needs an HDB permit.

Carpentry usually follows wet works, so cabinets and wardrobes are not fitted while floors and walls are still being tiled. Ask your contractor to check the waterproofing before the bathroom is tiled over.

Electrical and plumbing

If your inspection shows old wiring or pipes, decide early whether to replace them. The Energy Market Authority (EMA) says electrical work at home should be carried out or supervised by a Licensed Electrical Worker (LEW). EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. See EMA's page on engaging licensed workers.

Under HDB's electrical works guidelines, wiring must not be embedded in reinforced concrete slabs, beams, columns, walls or wall plaster; it is housed in metal or high-impact PVC conduit. New wiring can run behind carpentry, so agree the routes before carpentry starts. SP Services tests new wiring using Form CS/5H endorsed by HDB, applied for through your LEW.

PUB requires water service and sanitary plumbing works to be done by a PUB Licensed Plumber, except the listed simple plumbing works, such as replacing a tap or the flushing mechanism in a cistern, that a handyman may do.

Keeping to schedule

Book trades in sequence. Each one needs the stage before it finished: tiling follows first fix, carpenters take final measurements after wet works, and painters follow carpentry. Ask your contractor for a written schedule that shows each stage and who coordinates the trades.

Check works hours with your neighbours in mind. Hacking and drilling are noisy, so read our guide to HDB renovation hours before you fix dates, and let your neighbours know what is coming.

Changes in the middle of the works add time, and the cost depends on the job. Agree any change in writing before it starts. Before day one, run through the pre-renovation checklist so the paperwork and site arrangements are sorted.

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