What Will the Renovation Actually Cost? A 4-Room BTO, Priced Line by Line

The loan gets all the attention. The renovation is what actually empties the bank account. By the time a couple collects their BTO keys, they have spent two years thinking about the price of the flat and almost no time on the number that lands next — what it costs to make four bare concrete walls liveable. In 2026, with carpentry, labour and materials all dearer than they were even two years ago, that number is bigger than most first-timers guess.

So let's price one. Aaron and Lin are an illustrative composite — a couple we meet often, not real clients — collecting keys to a 4-room BTO this year. Their figures are stated assumptions; the line items and totals below are computed against current 2026 market rates, and they are deliberately mid-range: not show-home, not bare-minimum. This is what "normal" costs.

The contractor's quote: $47,000

Here is the renovation contract Aaron and Lin sign — the scope a typical interior firm quotes for a 4-room BTO done to a comfortable, not lavish, standard.

The single biggest line is carpentry, at $17,500 — about 37% of the contract. That is not unusual; across the industry carpentry routinely runs 25–40% of a renovation, because built-in cabinetry is labour-intensive and priced by the running foot. It is also the most controllable line in the whole budget. Every extra wardrobe, every full-height kitchen cabinet run, every custom feature wall adds hundreds. A couple who buys a few freestanding wardrobes instead of building them in can take thousands off this number; a couple who carpenters every wall can add as much again.

Notice what is low: hacking is just $800. That is the BTO advantage. The flat is new, so there are no walls to tear down, no old wiring to rip out, no concealed plumbing to chase. A resale flat of the same size would carry 20–40% more on exactly these structural lines.

The $13,900 nobody quotes you

Here is where budgets blow up. The contractor's quote is for renovation — it does not include the things that turn a renovated shell into a home. These get bought separately, often in a panic in the last fortnight, and they add up fast.

None of this is luxury. It is aircon, a working kitchen, safety grilles, light fittings and curtains — the baseline of an inhabitable flat. Add it to the contract and Aaron and Lin's all-in renovation is $60,900, not the $47,000 their contractor quoted. The gap between those two numbers is where first-timers run out of money. Budget the all-in figure, not the contract figure.

The ranges, by flat type

Aaron and Lin's flat is one data point. Here is the realistic 2026 spread for a mid-range BTO renovation, all-in, including the add-ons above:

Two rules of thumb fall out of this. First, each step up in flat size adds roughly $15,000–$20,000, almost all of it carpentry and flooring — more square metres to cover and more cabinetry to build. Second, resale is not BTO: take any row above and add 20–40% for the hacking, rewiring and replumbing an older flat needs. A resale 4-room that "looks the same size" can cost what a 5-room BTO does to renovate.

How to keep it honest

Three habits keep a renovation budget from running away. Quote the all-in, then hold 10% back as contingency — variation orders are a near-certainty, and a $6,000 buffer on a $60,000 job is the difference between calm and credit-card debt. Attack carpentry first, because it is the largest and most flexible line: decide what genuinely needs to be built in versus bought loose before you fall in love with a moodboard. And fund it deliberately — a renovation loan typically caps at six times monthly income or $30,000, whichever is lower, so a $60,000 job is part loan, part cash, and worth planning as such rather than discovering at signing.

The flat's price is fixed the day you book it. The renovation is the one big housing number you still control — but only if you price the real one, all-in, before the contractor's quote anchors you to the smaller half of it.

Aaron and Lin are an illustrative composite, not clients; their flat type and renovation scope are stated assumptions. Line items and totals are computed against mid-range 2026 market rates and will vary with your contractor, materials and choices. Renovation pricing is not a quote — always obtain itemised quotes from licensed renovators. General information only, not financial advice.

Sources: Qanvast — renovation cost calculator; MoneySmart — HDB renovation cost & loan guide 2026; ezID — 3/4/5-room HDB renovation budgets 2026. Ranges current as at June 2026.

Silas Tan is a District Director at Huttons Asia and co-founder of TRIBE. He built the Resale Project Scorecard (RPS) using 126,000+ URA REALIS transactions. This article is for informational purposes and does not constitute financial or investment advice. CEA Registration R000303I.