HDB Renovation: reno an old resale flat right

HDB Renovation on an ageing resale flat is a different game from a BTO. The bones are older, the wiring has seen decades of use, and the toilets may have hidden leaks. Doing it right means scoping the real problems first — hack, rewire, waterproof — before you fall in love with colours. Skimp on the essentials and a pretty flat turns problematic fast.

1. Start with a full condition check

Before any design talk, walk the flat like a building inspector. Look for cracks, water stains on ceilings, discoloured skirting, and musty smells near toilets. These tell you where the money should go. A resale 4-room flat in Singapore, based on recent market observations, often needs S$50,000 to S$80,000 or more of renovation once you include structural and services upgrades — so prioritising is key.

Bring in a BCA-licensed contractor listed on HDB's Directory of Renovation Contractors. Only they can apply for the renovation permit and carry out the regulated works legally.

2. Hacking and what you can't touch

Old flats often have tired tiles and partitions you'll want gone. But HDB rules are firm:

• No hacking of structural walls, beams, or columns.
• No shifting of toilets or hacking of parapet walls and floor traps.
• Corridor windows and main door position are restricted and can't be freely altered.
• Non-structural internal walls may be removed with HDB approval.

Confirm every hacking plan against HDB's guidelines before you start. The permit must be applied for within three months of resale completion and is valid for three months, with an inspection at the end.

3. Rewiring and electrical works

If the flat is old, the wiring likely predates modern loads — aircons, multiple fridges, home offices. Plan to upgrade the consumer unit and add power points where you'll actually need them: behind the TV, in the study, by the bed, in the service yard. Mention earlier planning points like extra data and aircon trunking so nothing gets buried mid-reno.

Electrical works must follow HDB's requirements and be done by a licensed electrician. This isn't the place to cut corners; faulty wiring is a fire risk.

4. Waterproofing the wet areas

Old toilet waterproofing is the most common silent failure. Before retiling, insist on a proper waterproofing membrane and a flood test. Leaks into the neighbour below are expensive and messy to fix after the fact.

Also check the kitchen floor trap and any balcony edge. If you're redoing the toilet, this is the only cheap moment to do it right — once tiles are laid, the cost to revisit multiplies.

5. Dealing with the deposit and timeline

For a 4-room and larger flat, HDB holds a renovation deposit of S$1,000, refunded only after a compliant end inspection. Plan your noisy works — hacking and drilling — for weekdays and Saturdays between 9am and 5pm, and never on Sundays or public holidays. Miss these windows and your neighbours will report you, risking your deposit.

Since 1 Oct 2024, CaseTrust's Renovation Framework applies to contracts of S$5,000 and above, giving you "Open Book" itemised pricing so you see material costs. Use it to keep the old-flat reno honest.

6. Build in the carpentry you'll keep

Once the bones are sound, add the storage that makes an old flat feel new: full-height wardrobes, a custom kitchen, a concealed shoe cabinet. This is where whole-house customization pays off, turning awkward old layouts into efficient ones. Scope the essentials first, then layer comfort — that order is what makes an old resale flat renovated right rather than just repainted.