The Permit Requirement
Most renovation work in an HDB flat requires a permit obtained through a registered renovation contractor who is enrolled with HDB. The homeowner cannot apply directly — the contractor applies on the owner's behalf after providing a formal quotation and work schedule. This arrangement places the contractor in the compliance chain: they accept responsibility for ensuring all work is carried out according to approved drawings and HDB's renovation guidelines.
The permit requirement applies to structural works, hacking of walls, alterations to sanitary fittings, electrical works, and any modification to floor finishes above the fourth storey. Minor cosmetic work — painting walls, installing shelving, or replacing door handles — generally does not require a permit, but the boundary is narrower than many residents assume.
Key rule: Renovation work that is structural in nature, affects wet areas, or involves removal of original HDB fittings always requires a permit from HDB before work begins. Starting without one exposes the homeowner to fines and a reinstatement order.
Permitted and Prohibited Works
HDB publishes a list of permitted and prohibited works that is updated periodically. The categories most relevant to typical flat renovations include:
Flooring
Laying new floor tiles or vinyl over existing floor finishes is permitted without structural involvement, provided the contractor ensures proper waterproofing in wet areas (kitchen, bathrooms, and service yard). Hacking out existing floor tiles down to the screed — a common practice to achieve a flat substrate — is a permitted work that requires a renovation permit. The total floor loading must not exceed the structural limits set in the flat's original design.
Walls
Non-structural partition walls built with lightweight materials (gypsum board, lightweight concrete blocks) may be erected or removed with a permit. Reinforced concrete (RC) walls and beams are structural elements and cannot be hacked, cut, or drilled for conduits without the submission of professional engineer (PE) drawings stamped by a licensed PE. HDB will not approve work on RC elements without these drawings, and any contractor who proceeds without them is operating outside the permit scope.
Wet Areas
Combining two bathrooms, relocating a toilet bowl, or changing the internal bathroom layout are among the more complex permitted works. All require waterproofing certification from the contractor upon completion. Bathrooms in HDB flats are designed with specific floor gradients to direct water toward the floor trap — any alteration that changes this gradient must be corrected as part of the scope.
Kitchen Works
The kitchen service yard, including the position of the washing machine point and the floor trap, may not be permanently sealed or blocked. Hacking the concrete partition between the kitchen and the service yard is a prohibited work in most HDB flat types. The kitchen exhaust duct — which runs vertically through multiple floors — may not be sealed or repurposed.
Noise and Working Hours
HDB renovation work that generates noise — hacking, drilling, sawing — is restricted to specific hours. As of the current guidelines:
- Monday to Friday: 9 am to 6 pm
- Saturday: 9 am to 1 pm
- Sundays and Public Holidays: no noisy works permitted
These rules are separate from those administered by the National Environment Agency (NEA) under the Environmental Protection and Management Act, which sets stricter decibel limits. Both sets of rules apply simultaneously. In practice, complaints from neighbours are one of the most common enforcement triggers, so contractors managing tight timelines need to schedule noisy works earlier in the renovation cycle.
Practical note: If you live in a relatively new HDB block where many units are renovating simultaneously — typical in the first year after a BTO project receives keys — noise schedules become particularly important, as the estate's management office may issue additional guidelines beyond the standard HDB restrictions.
Registered Renovation Contractors
Only contractors on HDB's approved list may apply for renovation permits. Homeowners can verify a contractor's registration status through the HDB InfoWEB portal. Unregistered contractors — even highly skilled ones — cannot obtain permits, and any work they carry out is automatically deemed unauthorised. If such work is later discovered during a resale inspection or by an HDB officer's visit, the homeowner — not the contractor — bears reinstatement liability.
When shortlisting contractors, the registration number and the company name on the HDB portal must match exactly. Several enforcement cases each year involve contractors trading under names similar to legitimate firms.
Permit Duration and Extensions
A renovation permit is typically valid for one month from the date of approval, with a maximum period of three months. If work cannot be completed within the permitted window — due to supply delays, concurrent BTO move-ins affecting lift access, or scope changes — the contractor must apply for an extension before the permit lapses. Continuing work under an expired permit is treated the same as working without a permit.
Completion and Inspections
Upon completing permitted works, certain categories require a post-completion inspection by an HDB officer. This is standard for structural works and major sanitary modifications. The contractor is responsible for notifying HDB and scheduling the inspection. Homeowners should retain all receipts, work orders, and inspection certificates — these documents are frequently requested during resale transactions and can also be relevant in the event of water seepage disputes with neighbours.
External Sources
Current renovation guidelines are published directly by the Housing & Development Board at hdb.gov.sg. The Building and Construction Authority's bca.gov.sg provides additional guidance on fire safety requirements for renovation works in residential buildings.