HDB Renovation: cost differences across flat sizes

HDB Renovation cost does not grow in a straight line with floor area, and that trips up owners who assume a 5-room flat simply costs "a bit more" than a 4-room. Size changes the amount of carpentry, the tiling, and the number of wet areas, but it also changes how you use the space — and that is where the real money moves.

Why a bigger HDB Renovation is not just "more of the same"

A 3-room flat has one bathroom and usually two bedrooms. A 5-room has two or three bedrooms and often two toilets. Each extra wet area multiplies plumbing, waterproofing, and tiling work, not just slightly more floor. So the jump from 3-room to 5-room is not double the cost — it is a different shape of job.

Market observations back this up. A 4-room BTO typically ranges from S$30k to S$50k. A 5-room BTO runs about S$40k to S$60k. The 5-room is not dramatically dearer per square foot, because some fixed costs — permit, design, coordination — stay put. But the total is higher because there is simply more to build.

3-room: spend on making it feel big

In a compact 3-room, the budget fight is against clutter, not against square footage you lack. Money here is best spent on full-height storage, a tidy bomb-shelter surround, and a layout that keeps the living area open. You do not need lavish finishing; you need smart carpentry that hides life.

Owners often overspend on a feature wall they barely see and underspend on storage they use daily. Flip that. A plain, durable wall and a well-built wardrobe beat a fancy panel you walk past.

4-room: the common middle ground

The 4-room is where most families land, and it carries the S$1,000 HDB deposit tier rather than the S$500 one, because the deposit steps up at 4 rooms and larger. That is a small thing, but it signals the flat is now in the "bigger" cost band.

Here the kitchen and the master bedroom wardrobe are the heavy hitters. A 4-room gives you room to build a proper wet-and-dry kitchen split, which adds carpentry and splashback cost but pays back every day you cook. The resale version of this flat, by the way, often runs S$50k to S$80k or more because of the tear-out and rewiring an older unit needs.

5-room and larger: carpentry volume drives the bill

With more bedrooms comes more wardrobe, more cabinetry, and often a study or a family nook. Carpentry volume is the main reason a 5-room costs what it does. The per-item price may be the same as a 4-room, but you are buying more items.

• Extra bedroom = one more full wardrobe.
• Bigger kitchen = more cabinet length and a wider counter.
• More walls = more painting and possibly more false ceiling to conceal trunking.

None of this is wasted if the space is used. The trap is building for rooms nobody lives in. A guest room wardrobe you open twice a year can be lighter than the one in your bedroom.

Match the budget to how you actually live

The honest way to compare sizes is to ask what each room is for. A 3-room rewards storage smarts. A 4-room rewards a strong kitchen and master suite. A 5-room rewards restraint in the spare rooms so the daily spaces shine.

Size sets the floor of your cost, but your habits set the ceiling. Plan around the rooms you use, respect the deposit and permit rules that apply at every size, and your HDB Renovation spends in proportion to real life rather than to square footage alone. If you want those trade-offs mapped to your exact flat, our whole-house customisation is built to show you where each dollar earns its place.