9 Best Resale HDB Interior Design Firms in Singapore (August 2026)

Before the list, the checks that matter most for an older flat. As with any HDB work, the firm must be on the HDB Directory of Registered Renovation Contractors, and for a resale flat that is doubly important, because more of the work, hacking walls, moving wet areas, rewiring, needs to follow HDB rules and, in some cases, formal approval.

Deposit protection matters here too. Resale renovations are bigger and pricier than BTOs, so I look for firms under the CaseTrust-RCMA accreditation scheme, which requires a standard contract and deposit protection. When you are paying six figures in stages, that safety net earns its keep.

Then the resale-specific judgement. Older-flat experience: ask to see recent resale projects of a similar age and layout, not just glossy BTO shots, because reworking a 30-year-old flat is a different skill. Honest pricing for the unknowns: good firms flag that hacking, rewiring and re-plumbing carry some uncertainty until the walls are open, and build a sensible contingency in rather than lowballing the quote and hitting you with variation orders later. And layout vision: the real value in a resale is often a smarter floor plan, so you want a designer who can see past the previous owner's choices. Treat this as a shortlist to interview, matched to your flat.

Resale renovations usually cost more than a comparable BTO, because you are paying to undo and redo before you even reach the finishes. Hacking, rewiring, re-plumbing and new flooring across a whole flat add up fast. Here are the ballpark design-and-renovation ranges I would budget for in 2026, excluding furniture and appliances.

How much you reconfigure is the biggest variable. A light cosmetic refresh sits at the bottom of these ranges, while gutting the flat, moving the kitchen and re-planning the layout pushes toward the top. Always get an itemised quote with a contingency line, because older flats reliably reveal something once the walls are open.

Here is the shortlist in one view, by what each firm does best for an older flat.

I weight Qanvast reviews that describe the process and after-sales service, cross-check HDB renovation-contractor registration and CaseTrust-RCMA accreditation, and favour firms with genuine resale experience and honest pricing for older-flat unknowns. Ratings and details were accurate when I wrote this but they move, so confirm the current picture with each firm before you sign. I update the list when my view changes.

Because you pay to remove before you pay to build. A new BTO starts clean, so the money goes straight into carpentry and finishes. A resale flat usually needs hacking of old fixtures and walls, rewiring of ageing electrical, re-plumbing, and full replacement of dated flooring and bathrooms before any of the nice work begins. Those hidden-layer works add cost and time, which is why a resale renovation of the same size typically runs noticeably higher than a BTO.

Structural and safety-related works are the ones to watch: hacking or removing walls, changing the position of wet areas, replacing windows, and certain electrical and plumbing changes generally require HDB permission, and some works are not permitted at all. A registered renovation contractor will handle the submissions and know what is and is not allowed, which is one more reason to use a firm on the HDB register of renovation contractors. Never let anyone hack a wall without confirming it is approved.

Longer than a BTO, typically around 10 to 16 weeks once works start, plus a few weeks for design and material selection. The extra time comes from the demolition and hidden-layer works, hacking, rewiring, re-plumbing, that a new flat does not need. If your flat is old or you are heavily reconfiguring the layout, build in a generous buffer and do not commit to a hard move-in date until the works are well underway.

Often yes, because a smarter floor plan is where a resale renovation adds the most value, an open kitchen, a better-placed bedroom wall, more usable storage. But hacking is also the most expensive and disruptive part, and some walls cannot be touched. The right approach is to have a designer assess which changes are worth the cost and which are structurally or legally off-limits, then reconfigure with intent rather than hacking for the sake of it. A good resale firm will talk you out of changes that do not pay for themselves.