HDB Flat Renovation Rules Singapore 2026: What Requires Approval, What Is Prohibited, and Agent Guidance for Resale Buyers

Disclaimer (Block 1): This article is for educational purposes only and is intended to assist CEA-registered property agents in understanding regulatory frameworks. It does not constitute financial, tax, or legal advice. LEVR's calculations are indicative only. Always verify rates and eligibility with your bank, HDB, CPF Board, or a licensed financial advisor before advising clients.

Overview of HDB Renovation Rules

Renovations to HDB flats are regulated by the Housing and Development Board (HDB) under the HDB renovation guidelines. These rules exist to preserve the structural integrity of HDB blocks, maintain fire safety standards, protect common areas and neighbouring units, and ensure that renovations are carried out by licensed contractors.

HDB renovation rules apply to all HDB flat owners — whether they are the first owner doing a new flat renovation or a resale buyer making changes to a secondhand flat. The rules cover both structural works (that require formal HDB approval) and non-structural works (that are permitted without approval but must still comply with HDB guidelines).

Works Requiring HDB Approval

Certain renovation works must be approved by HDB before they commence. These include:

• Hacking of walls: Removing internal walls (other than lightweight partition walls) requires HDB approval. Structural walls — which support the building — cannot be hacked regardless of approval. Agents should advise buyers who intend to open up their flat layout to check the structural wall plan with their contractor and obtain HDB approval before proceeding.
• Enlarging door and window openings: Widening or enlarging door or window openings in structural walls requires approval.
• Installation of grilles on external windows:Window grilles on the external facade of the building (including corridor-facing windows) must be installed in accordance with HDB specifications and may require approval depending on the installation type.
• Bathroom and toilet works involving drainage:Alterations to floor traps, drainage pipes, or the waterproofing membrane of bathroom floors require approval and must be done by an HDB-registered contractor.
• Roof works (for maisonettes): Works on the roof slab of maisonette-type HDB units require approval.
• Electrical load additions exceeding the approved capacity: Increasing the electrical load of the flat beyond the approved capacity requires SP Group and potentially HDB approval.

Works Permitted Without Prior Approval

The following works generally do not require prior HDB approval but must comply with HDB renovation guidelines and be carried out by licensed contractors:

• Repainting interior walls and ceilings: Painting the interior of the flat does not require approval.
• Replacing flooring: Laying new tiles, vinyl, or timber flooring within the flat does not require approval, but the weight loading of the flooring material must not exceed the permitted structural load, and installation must comply with HDB guidelines.
• Replacing kitchen and bathroom fixtures: Replacing sinks, toilets, bathtubs, and kitchen fixtures at the same location (without altering drainage positions) generally does not require approval.
• Installing kitchen cabinetry and built-in wardrobes: Standard carpentry installation within the flat does not require approval.
• Hacking lightweight partition walls: Non-structural lightweight partitions (identifiable from the structural wall plan) can typically be removed without approval, but the contractor should confirm the wall type before commencing.
• Replacing internal doors: Replacing internal doors does not require approval, provided the door frame and structural opening are not altered.

Prohibited Works

Certain works are prohibited outright and cannot be approved regardless of circumstances:

• Hacking structural walls: Structural walls that carry the load of the building above cannot be removed or significantly altered. Doing so endangers the structural integrity of the block.
• Enclosing corridor areas or common property: HDB flat owners may not enclose, gate off, or occupy common corridor space as part of their flat. This is a persistent issue in older HDB estates.
• Merging two adjoining units without approval:Connecting two adjacent units by creating openings between them requires approval and is subject to strict HDB conditions; informal merging without approval is prohibited.
• External alterations visible from the facade: Adding external air-conditioning ledges, extending balconies, or making changes visible from the building exterior is generally prohibited without HDB approval.
• Converting living areas to wet areas without waterproofing: Creating bathrooms or wet areas in spaces that were originally dry without proper waterproofing is prohibited as it creates water leakage risk to neighbouring units below.
• Works by unlicensed contractors: Structural works must be carried out by HDB-registered contractors. Using unlicensed contractors for structural renovation work is a breach of HDB rules.

Identifying Unauthorized Works in Resale Flats

Unauthorized renovations in resale flats are a known issue. Buyers and their agents should be vigilant:

• Request the renovation permit history: Sellers can obtain the renovation permit records from HDB. Agents acting for buyers should request this documentation as part of due diligence. Any renovation carried out without the required permit is technically unauthorized.
• Check for structural wall removal: If the flat appears to have an open-plan layout that was not part of the original design, enquire whether walls were removed and whether HDB approval was obtained.
• Inspect bathroom and kitchen drainage: Unauthorized repositioning of drainage outlets or floor traps can cause leakage to the unit below. Water damage to the ceiling of the flat below may be a sign of unauthorized drainage works above.
• Check corridor enclosures: Unauthorized corridor enclosures (gated-off or built-up corridor areas) must be removed. If the seller has enclosed corridor space, HDB may require this to be reinstated before the resale can proceed.
• Consequences of buying with unauthorized works: If a resale buyer purchases a flat with unauthorized renovations, the buyer (as the new owner) becomes responsible for rectifying the works at their own cost if HDB issues a notice to reinstate. The buyer cannot recover rectification costs from the seller unless the SPA specifically provides for this.

Guidance for Property Agents

• Advise buyers to check renovation permit records: Encourage buyer clients to request the renovation permit history from the seller and have the flat inspected by a qualified building inspector (or their own licensed contractor) before exercising the OTP.
• Flag visible signs of unauthorized works: If you notice features during a viewing that appear inconsistent with standard HDB layouts — knocked-through walls, enlarged openings, corridor enclosures, unusual wet areas — flag these to your buyer client and advise them to seek clarification before committing.
• Do not misrepresent renovation status: If you are acting for the seller and are aware of unauthorized renovations, do not represent the flat as having standard renovation or hide the non-compliant works. Disclosure of material facts is a professional obligation.
• Include renovation condition in negotiations: If unauthorized works are discovered, buyers can negotiate for the seller to rectify before completion or for a price reduction to cover the cost of rectification. The specific approach should be agreed by the parties and reflected in the OTP or SPA.
• Direct clients to HDB for confirmation: For buyers who plan significant renovations after purchase, direct them to HDB to confirm which works require approval and which contractors are HDB-registered before they begin planning.

Summary

HDB renovation rules require approval for structural works including hacking of non-lightweight walls, enlarging openings, bathroom drainage alterations, and certain electrical upgrades. Structural wall removal, corridor enclosures, and unauthorized extensions are prohibited outright. Non-structural works like repainting, flooring replacement, and fixture replacement generally do not require approval but must comply with HDB guidelines. Unauthorized renovations are common in resale flats. Buyers should request renovation permit records, inspect the flat carefully, and consider a building inspection before committing. Buyers who purchase a flat with unauthorized works become responsible for rectification costs if HDB issues a reinstatement notice. Agents should flag visible irregularities and advise clients to conduct thorough due diligence before exercising the OTP.

Disclaimer (Block 3): LEVR's calculator outputs are estimates based on inputs provided and current regulatory parameters as known at time of publication. They are not a guarantee of borrowing capacity, stamp duty liability, or CPF eligibility. Regulatory thresholds and rates may change. Always verify with IRAS, your bank, or a licensed financial advisor before making financial decisions.