Periodic Structural Inspection (PSI) is a Building and Construction Authority inspection of a building's structure, carried out in person by a registered structural engineer. BCA serves a notice: every five years for non-residential buildings, every ten years for residential ones. The owner appoints and pays, and the owner submits the report.
The regime sits in Part 5 of the Building Control Act 1989 and in Part 2 (regulations 3 to 7) of the Building Control (Periodic Inspection of Buildings and Building Façades) Regulations 2021. The Regulations define a structural inspection simply as "an inspection of the building to ensure its structural stability or integrity".
Which buildings are in scope
Part 5 applies to all buildings other than detached, semi-detached, terraced or linked houses used solely by their owners or occupiers as their residence, and temporary buildings (s.27(1)). Two points that catch people out:
- There is no height threshold. The 13 metre exclusion at s.27(3)(b) applies only to Periodic Facade Inspection. A low-rise non-residential building is squarely inside the structural regime.
- Fixed installations count. Under s.27(2), the structural inspection requirements apply to fixed installations, whether or not associated with another building, as if the fixed installation is a building.
A building physically connected to another is treated as a separate building if it could remain in position and be used independently, or would need only minor modification to do so, and a connection at or below ground level or by a bridge does not stop it being separate (s.26(2)).
The interval: five years or ten, and no thirteenth year
Do not plan around a thirteenth-year trigger. Several third-party sites state that PSI falls due in the thirteenth year. No such threshold appears anywhere in the Building Control Act. The only 13 in the periodic inspection regime is the facade height exclusion: PFI does not apply to a building whose highest point is 13 metres or lower. The structural intervals are these:
- Non-residential (s.28(2)(a)). A notice may be given after the 5th year commencing from the date the first TOP or first CSC was issued, whichever was issued earlier, and thereafter at intervals of not less than 5 years from the date of the last notice.
- Residential or a "special building" (s.28(2)(b)). A notice may be given after the 10th year on the same basis, and thereafter at intervals of not less than 10 years. A special building is defined at s.26(1) as any building of which not less than 90% of its floor area is used solely for residential purposes.
- No TOP or CSC ever issued (s.28(2A)). The Commissioner may give notice at any time he considers appropriate, and thereafter at the 5 or 10 year intervals as applicable.
BCA restates it plainly in its Guidelines for Structural Engineers: every 10 years for buildings where at least 90% of the floor area is used solely for residential purposes, and every 5 years for all other buildings.
One nuance worth carrying into your compliance calendar. The statutory formula is a minimum interval between notices, not a self-executing calendar duty. The obligation on the owner arises when the Commissioner serves a notice under s.28(1)(a). If you cannot find the TOP or CSC date that starts the clock, BCA will supply it: see Certificate of Statutory Completion.
Who must carry it out
A structural engineer, defined at s.26(1) as a person registered under the Professional Engineers Act 1991 in the civil or structural engineering discipline who has in force a practising certificate authorising him to engage in civil or structural engineering work. BCA explains why in its Guidelines: the inspection needs professional assessment and judgement in structural engineering during the visual inspection.
Personal presence is not optional. BCA's Guidelines para 2.2 states that it is "not an acceptable practice for the structural engineer to not visit the building or to delegate the entire inspection work to his/her assistant or any other person who is not a registered professional engineer" in the civil and structural discipline. BCA Circular APPBCA-2026-02 of 2 March 2026 goes further: "BCA requires the appointed SE to personally conduct the PSI and be physically present during inspection, as the SE's professional judgment, expertise, and direct observation are fundamental to a meaningful and effective inspection."
The engineer must have no professional or financial interest in the building (s.29(1)). He is treated as having one if he is or has been responsible for the design or construction of the building or any of the building works in any capacity, except alterations that do not affect a key structural element or whose effects are localised and require no strengthening of a key structural element (s.29(2)).
Who counts as the owner
For a subdivided building comprised in a strata title plan, the owner is the management corporation having control of the common property, or the person receiving rent or charge for its maintenance and management. For limited common property, it is the subsidiary management corporation. For common property of residential and commercial property in an HDB housing estate, it is the Housing and Development Board. For unsubdivided premises, it is the registered proprietor of the fee simple, estate in perpetuity or leasehold estate (s.26(1)).
Where a building comprising two or more flats is not subdivided and there are subsisting registered leases, the owners must jointly appoint the structural engineer (s.28(4)), and BCA's Guidelines add that the engineer may commence only after being jointly appointed by all owners. The appointed engineer has a right of access at any reasonable time in the day to any part of the building (s.28(5)); obstructing it is an offence.
Stage 1: the visual inspection
Under reg 6(2), the structural engineer must personally carry out a visual survey of:
- the condition of the building;
- the loading on the structure of the building; and
- whether there is evidence of any structural works that are or were carried out without any prior approval of the plans of those works where prior approval is required by Part 2 of the Act.
Limb three is a statutory duty to hunt for unauthorised works, and it is the reason approved plans matter so much to this inspection. Where unauthorised works are found, BCA's Guidelines require the engineer to state whether they have caused excessive loading or other adverse effects, and to advise the owner to demolish or regularise the structure.
How much of the building has to be inspected
The visual inspection shall cover all structural elements within the building or buildings at the stated address. Where reduced coverage is unavoidable, BCA's Guidelines for Structural Engineers (September 2024) set minimum sampling.
Residential developments
| Requirement | Threshold |
|---|---|
| Special and critical structures, and structures without redundancies | Must be visually inspected. Where concealed by architectural finishes, access shall be made to inspect the concealed structure. |
| Structural elements in common areas (corridor, stairway, lift lobby, clubhouse) | Must be inspected. |
| Residential units accessed | At least 20% for a building 30 years old or less, 30% for a building over 30 years old. All rooftop units. At least 1 unit per storey on all other storeys, well distributed across wings, applied to each and every block or tower. |
| Cladded columns | Expose at least 30% for inspection, more if professional judgement requires. The owner shall arrange for the removal of the claddings or concealments. |
BCA states that meeting those requirements means the structural engineer can expect to visually inspect at least 70% to 80% of the building's structural elements.
Non-residential developments
| Requirement | Threshold |
|---|---|
| Indoor areas not exposed to weather, covered by suspended ceilings | At least 1 suspended ceiling accessed every 500 m² |
| Outdoor weather-exposed areas covered by suspended ceiling | At least 1 suspended ceiling accessed every 250 m² |
| Cladded columns | Expose at least 30%, more if professional judgement requires. The owner shall provide access and arrange for removal of the claddings or concealments. |
Annex D of the Guidelines adds recommended coverage for older buildings, unless the building has undergone major structural improvement or strengthening works: 40% of residential units for buildings over 40 years old, and 60% for buildings over 60 years old. For non-residential developments, increased coverage means accessing suspended ceiling panels at intervals smaller than the 500 m² and 250 m² baselines.
Stage 2: the full structural investigation
Triggered where, after the visual inspection, the engineer reasonably suspects a defect, deformation or deterioration likely to endanger or reduce structural stability or integrity, and is of the opinion that a full investigation is necessary. It may be carried out only with the prior approval of the Commissioner, on an application accompanied by an interim report describing the visual inspection in detail (reg 6(3)).
Under reg 6(4), a full structural investigation includes:
- taking all reasonable steps to obtain information on the design, construction, maintenance and history of the building;
- checking with reasonable diligence the structural plans of the building and the calculations contained in them, or if the plans cannot be obtained, reconstructing with reasonable diligence such structural plans where the Commissioner so requires;
- tests on the structural elements, without damaging any part of them;
- tests on the materials used in construction; and
- load testing of such parts of the building as the structural engineer considers necessary.
The owner may engage a different structural engineer for Stage 2, and should inform BCA by written notice before that inspection is carried out.
Structural plans: getting them, and what if there are none
Three separate things get muddled here, so keep them apart.
Record plans are a construction-stage deliverable. The Building Control Regulations 2003 define a "record plan" as a plan showing the immaterial changes made to the building works of the approved or deemed approved plan. On completion of structural works the QP (Design) submits the Certificate of Record Structural Plans/Calculations, Form BCA-BE-CTASST, previously BEV C3. That is a defined submission by a defined person. A survey deliverable is not a record plan.
The engineer must obtain the plans from BCA before inspecting. Guidelines para 3.1: prior to commencing the visual inspection, the structural engineer is required to obtain a set of the building's latest structural layout plans from BCA, in order to understand the structural system, identify special and critical structures and structures without redundancies, identify small, narrow or slender reinforced concrete columns in void decks of pre-1989 residential buildings, identify the allowable imposed loads so overloading can be assessed, and identify structural works carried out without prior approval.
Owners buy those drawings through BCA's Plan Purchase service. Under BC Regs reg 49 the search fee is S$45 per address and a copy costs a further S$65 for each set of approved drawings uniquely identified by a reference number. BCA responds on availability within 10 working days. Eligible applicants include a registered proprietor, staff of a corporate registered proprietor, the Chairman of a Management Corporation Strata Title, and an authorised person representing any of them, each with the stated supporting documents.
When the plans do not exist. Nothing in the Act or Regulations excuses an owner from PSI because plans are missing, and nothing should be read that way. What the Regulations do instead is provide for reconstruction: reg 6(4)(b)(ii) requires the structural engineer, where the plans cannot be obtained, to reconstruct them with reasonable diligence where the Commissioner so requires. BCA's Guidelines para 4.2 adds that where 100% coverage is not possible, "Reference to structural layout plans to determine the presence of special and critical structures and structures without redundancies would be crucial under such circumstances". Without plans, the sampling basis itself becomes harder to defend. Annex A, the mandatory report checklist, opens with "Reference to structural layout plans and details".
If BCA's search comes back empty, measurement is the only remaining route to a usable document set. That is the work behind structural inspection survey support and what to do when the floor plan is missing or wrong.
Deadlines and penalties
| Step | Deadline | Maximum fine |
|---|---|---|
| Owner appoints a structural engineer | Within 2 months after the date of the notice, or any extension allowed | S$20,000 |
| Owner appoints a replacement structural engineer | Within 2 months after becoming aware the first cannot or will not continue | S$20,000 |
| Owner notifies the Commissioner of the appointment | No later than the 7th day, or the next working day, after the end of the 2 month period | S$10,000 |
| Inspection completed and report submitted by the owner | Within the period specified in the notice. The Act fixes no standard number of months. | See below |
| Recommended remedial works carried out | Within such period, and subject to such conditions, as the Commissioner specifies | See below |
An engineer who needs more time must apply to BCA for a written extension at least 5 days before the deadline (BCA PSI Guidelines, para 2.3).
- Owner contravenes or fails to comply with a periodic inspection notice: fine up to S$20,000 (s.28(8)).
- Owner, without reasonable excuse, fails to appoint, fails to submit the report, or fails to carry out the recommended works: fine up to S$20,000 or imprisonment up to 12 months or both, plus up to S$500 for each day of continuing contravention, and up to S$2,000 a day if it continues after conviction (s.28(9)).
- Structural engineer fails to carry out the inspection in the prescribed manner, prepare the report, give it to the owner, or comply with the Commissioner's directions: fine up to S$50,000 (s.28(10)).
- Hindering, obstructing or delaying a structural engineer exercising the statutory right of access: fine up to S$5,000, plus up to S$500 a day of continuing offence after conviction (s.28(5A)).
What BCA has publicly criticised
Circular APPBCA-2026-02 lists the practices BCA regards as unacceptable. It is unusually direct, and it tells owners what a defensible inspection looks like:
- Engineers delegating inspections entirely to staff or third parties while not being present.
- Fraudulent documentation: inspection photographs from previous cycles passed off as photographs taken in a later cycle.
- Inadequate coverage against the minimum requirements in the PSI Guidelines.
- Inadequate assessment of concealed or cladded structures. BCA states that architectural finishes alone do not indicate structural condition and may mask underlying structural defects, and that borescopes, scanners and miniature robotic cameras must be used where necessary.
- Failure to report unauthorised structures, including their structural framing, area, and effects on the main building.
- Failure to detect a change of use and verify imposed loading, particularly conversions from residential to commercial in shophouses. BCA expects owners of non-residential buildings to exhibit a floor diagram with markings of the design load on every storey, verified against the plans approved by the Commissioner.
That last item is a documentation task before it is an engineering one. A floor diagram marked with design loads needs a current, accurate plan of each storey to sit on, which is ordinary as-built documentation work.
What a scan can and cannot do
Stated precisely, because this audience will check it.
It can:
- Record the geometry and visible condition of a building at a specific date, to a stated accuracy, with full coverage of what is visible from the survey positions.
- Produce elevation drawings, floor plans, sections and reflected ceiling plans of an existing building where none exist or where the existing ones are unreliable.
- Support a comparison between as-built condition and approved plans, which BCA itself recommends owners and prospective buyers carry out.
- Supply the geometric basis from which a Professional Engineer may reconstruct structural plans, which the Building Control (Periodic Inspection of Buildings and Building Façades) Regulations 2021 expressly contemplate at reg 6(4)(b)(ii) for buildings and reg 15(6)(b)(i)(B) for facades.
It cannot:
- Be a statutory inspection. Periodic Structural Inspection is a Professional Engineer's personal act, and BCA said in March 2026 that the engineer must be physically present. Periodic Facade Inspection is a competent person's personal act under reg 16(1).
- Determine structural capacity, reinforcement, concrete grade, connection condition or load path.
- Detect concealed defects. Surface capture records the finish, not the structure or the fixings behind it.
- Replace opening up. The obligation to arrange removal of claddings and concealments sits with the owner.
- Be a building plan, a record plan, a schedule of dilapidations, a strata title plan, a valuation, or an as-built plan under Planning Act s.20A. Each of those has a defined author.
- Regularise unauthorised works, satisfy a developer's handover obligation, or discharge any statutory duty.
Measured documentation is the input that lets the engineer do their statutory job properly, and the evidence that survives a dispute. If a notice has landed and your drawing set will not support it, tell us the building type, age and floor count and we will scope the capture around your engineer's programme.