How much to renovate a 4-room HDB?

A BTO is roughly S$40k–S$62k; a resale flat S$65k–S$150k depending on hacking, rewiring and finishes. Qanvast puts the average resale HDB reno around S$67k.

What are the HDB renovation rules?

Use a DRC-listed contractor, get HDB approval for any hacking, and keep to permitted hours: general work 9am–6pm Mon–Sat; noisy work 9am–5pm weekdays only, finished within 3 consecutive days.

Renovation Cost in Singapore by Flat Type (2026)

Q: Why do resale flats cost more?

Older flats usually need hacking, rewiring, new plumbing and waterproofing — adding 20–40% versus a new BTO.

Renovation is usually the biggest cheque you’ll write after the home itself, and the range is enormous — from a light refresh to a full gut-and-rebuild. Knowing the typical 2026 costs by flat type, and the HDB rules you must follow, lets you budget realistically and avoid nasty surprises. Here’s the full picture.

Typical costs by flat type

4-room BTO: roughly S$40,000–S$62,000 for a full renovation; a basic scope can come in lower.
4-room resale: roughly S$65,000–S$150,000, with the industry average for a resale HDB reno around S$67,000 (per Qanvast).
Scale down for a 3-room flat, up for 5-room and condos.

These are guides, not quotes — your actual cost depends heavily on scope, materials and how much structural work is involved.

Why resale flats cost more

Resale flats typically cost 20–40% more to renovate than a comparable BTO, because older units usually need hacking, rewiring, new plumbing and waterproofing on top of the cosmetic work. If your resale flat is in good condition and you keep the existing layout and wet areas, you can save a great deal by avoiding those big-ticket items. The biggest cost drivers are almost always structural changes and wet works — carpentry, tiling and hacking — rather than paint and fittings.

The HDB rules you must follow

Renovation is regulated, and breaking the rules can mean fines or being ordered to reinstate work:

Only contractors on HDB’s Directory of Renovation Contractors (DRC) may carry out the work.
Any hacking or demolition of walls needs HDB’s written approval, to protect the building’s structural integrity.
Permitted hours: general renovation is 9am–6pm Monday to Saturday (none on Sundays and public holidays). Noisy work — hacking, tile-cutting, heavy drilling — is restricted to 9am–5pm on weekdays only, must be completed within three consecutive days, and isn’t allowed on Saturdays, Sundays, public holidays or certain eves.
Contractors are limited in the power tools they can use at once.

A good DRC contractor handles the permits, but it’s your project — know the rules so you can hold them to it.

What drives your price

Beyond BTO-vs-resale, the main cost levers are: the amount of carpentry (built-in wardrobes and kitchen cabinetry are expensive), the extent of hacking and wet works, the quality of materials and finishes you choose, and whether you’re changing the layout. Trimming any of these trims the bill. Fixtures and fittings are usually a smaller share than people expect; carpentry and structural work dominate.

How to save without cutting corners

Get two or three itemised quotes so you can compare like for like and spot padding. Keep wet areas (kitchen and bathrooms) where they are to avoid re-plumbing and re-waterproofing. Phase non-essential works so you spread the cost. And be realistic about carpentry — freestanding furniture is far cheaper than built-ins and moves with you. Our guide to electrician, plumber and handyman costs helps with smaller standalone jobs.

Budgeting for the whole project

Remember renovation isn’t the only move-in cost. You’ll also furnish the place (see furnishing on a budget and the cost of furnishing a flat), possibly buy aircon, and pay for the move itself. Build a total budget so a big renovation doesn’t leave nothing for the rest.

The bottom line

Expect roughly S$40k–S$62k for a 4-room BTO and S$65k–S$150k for a 4-room resale, with resale costing more because of hacking, rewiring and waterproofing. Use a DRC contractor, get HDB approval for any hacking, respect the permitted hours, and get itemised quotes. Control the big levers — carpentry, wet works and finishes — and you control the bill. Compare quotes from vetted firms using the form below.

Where the money actually goes

It helps to know which parts of a renovation cost the most, so you can focus your budget. Carpentry — built-in wardrobes, kitchen cabinetry, feature walls and shelving — is typically the single biggest line item. Wet works (tiling, waterproofing and plumbing in kitchens and bathrooms) come next, followed by hacking and structural changes. Painting, lighting and loose fittings are usually a smaller share than people assume. If you need to trim the budget, scaling back carpentry (fewer built-ins, more freestanding furniture) and avoiding layout changes to wet areas saves the most.

Contractor vs interior designer

You can renovate through a contractor (you direct the works and design) or an interior design (ID) firm (which designs and project-manages, usually at a higher cost). A contractor is cheaper and fine if you have a clear plan and time to coordinate; an ID firm costs more but handles the design, coordination and problem-solving, which many people find worth it for a major renovation. Either way, use a firm on HDB’s Directory of Renovation Contractors, get itemised quotes, and check reviews and past work before committing.

Protecting yourself

Renovation disputes usually come from vague scopes and verbal agreements. Protect yourself with a detailed, itemised contract that specifies exactly what’s included, the materials and finishes, the timeline, the payment schedule (avoid paying too much upfront), and who’s responsible for permits and debris removal. Keep the renovation to permitted hours, ensure hacking has HDB approval, and document the work as it progresses. A clear contract and a reputable, DRC-listed firm are your best defence against cost blowouts and half-finished work. Compare quotes from vetted firms using the form below.

A quick budgeting summary

To summarise: expect roughly S$40,000–S$62,000 for a 4-room BTO and S$65,000–S$150,000 for a 4-room resale, with resale costing more because of hacking, rewiring, new plumbing and waterproofing. The biggest cost drivers are carpentry, wet works and structural changes — control those and you control the bill. Use a contractor on HDB’s Directory of Renovation Contractors, get written HDB approval for any hacking, and keep strictly to the permitted working hours to avoid penalties. Get two or three itemised quotes so you’re comparing like for like, insist on a detailed contract with a sensible payment schedule, and don’t pay too much upfront. Build a total move-in budget that also covers furnishing, aircon and the move itself, so a big renovation doesn’t leave you short for everything else. Done carefully, you get the home you want without the cost blowouts that catch out unprepared homeowners.