Household shelter rules in an HDB flat: what you may and may not do to a bomb shelter

Painting the walls, ceiling and door of a household shelter is permitted, as is laying vinyl or cement-bedded floor tiles, and drilling shallow holes for removable screws. Hacking the structure, modifying or removing the steel door, tampering with the ventilation sleeves, and covering the notice on the inside face of the door are all prohibited. SCDF's published list of permitted works caps drilling at a depth of not more than 50mm into the internal faces of the shelter walls and ceiling slabs. Section 4(2) of the Civil Defence Shelter Act 1997 sets a fine of up to $5,000 for an alteration likely to impair the efficient use of a household shelter, unless the Commissioner has given written permission.

What a bomb shelter in Singapore actually is

Section 3 of the Civil Defence Shelter Act 1997 requires every new house to be provided with a household shelter in accordance with the specifications, and every new building subdivided into flats to have either a household shelter in every flat or at least one storey shelter on that storey. Most owners call the room a bomb shelter; in everyday Singapore Chinese it is 防空壕, and the literal rendering of the official English name is 家用避难所. HDB's renovation guidelines put the purpose in one line: "The HS in your HDB flat is designed to serve as a civil defence shelter. It is fitted with a steel door, along with strengthened floor, walls and ceiling to protect occupants in the event of a wartime emergency."

Peacetime use of the room is expected rather than tolerated. Clause 1.3 of SCDF's Technical Requirements for Household Shelters 2023 states that every HS "shall be designed to a specific peacetime use", and Clause 2.7.1(d) allows fixtures such as cabinets and shelves "provided they are easily dismantled and removed". Storage that cannot be cleared out fast is the problem.

What SCDF permits inside a household shelter

The controlling document is a two-page SCDF list, *Permitted and Not Permitted Works for Household Shelters (HS)*, reproduced almost word for word in HDB's renovation guidelines for building works. Permitted works are:

• Floor tiles bonded to wet cement mortar, where the total thickness of floor finishes and screed does not exceed 50mm.
• Vinyl or linoleum flooring.
• Floor skirting tiles up to a maximum of 100mm high, bonded with wet cement mortar to the shelter walls.
• Splatter dash or equivalent on the external face of the walls only, to provide a rough surface for feature wall panels or wall tiles.
• Painting of walls, ceiling or door, subject to the door conditions below.
• Painting of the exterior face only of the 6mm stainless steel fragmentation plate on each ventilation sleeve.
• Drilling into the internal face of the walls and ceiling slabs to a depth of not more than 50mm, to affix non-metallic inserts and removable screws.
• Power driven nails on the external face of the walls, nail length not more than 75mm.
• Removing the fragmentation plates, provided the plates and their bolts and nuts are mounted or kept together for use when needed.

Your house has a civil defence shelter. It is designed to protect you during a war emergency. It has strengthened walls, floor, ceiling and a specially designed door. They must not be hacked or drilled. Certain finishes and fixtures are not permitted as they are not easily removable and may become hazards to shelter occupants during a war emergency.

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— Singapore Civil Defence Force, *Permitted and Not Permitted Works for Household Shelters (HS)*, paragraph 1(a)

What is not permitted, in full

The prohibited list in that same SCDF document is short enough to read before signing a renovation quotation:

• Wall tiles, rock tone finish, cement sand finish or gypsum plastering on the internal faces of the walls.
• Floor tiles laid with adhesive materials, or a second layer of floor or skirting tiles.
• Cornices installed within the shelter.
• Fixings using power driven nails into the internal walls.
• Tampering with, removing or covering up the HS door notice.
• Indiscriminate hacking and drilling of the walls, floor slabs and ceiling slabs beyond the drilling described above.
• Hacking either face of the walls to form a key for tiling.
• Hacking the external face of a wall to mount feature wall panels or wall tiles.
• Modifying, changing, removing or tampering with the HS door and frame.
• Modifying, altering or tampering with any part of the ventilation openings, plates and mounting devices such as bolts and nuts.
• Painting the interior face of the fragmentation plate, the ventilation sleeves, the "O" ring rubber gaskets, or the stainless steel bolts holding the plate to the sleeve.

Two entries account for most accidental breaches. Contractors chasing conduits or fixing a feature wall panel will hack a wall face for grip, and painters spray the whole interior including the sleeve and its gasket.

The steel door and the notice people paint over

Painting the door is allowed; the door notice is not paintable. HDB's building works guidelines require the old paint coat on door and frame to be removed before repainting, so that added thickness does not make the door hard to close and open, and require the new coat to dry completely before the door is shut, because wet or damp paint makes the door and rubber gasket stick to the frame. Covering the notice, the locking bolts or the door seal is prohibited outright, and SCDF's list explains why: the notice "provides important information to the occupants on the use of the HS".

Hinges fail for a mundane reason. HDB's home care guide for household shelters explains that repeatedly swinging the door so that it knocks against the skirting tiles "induces stress to the door hinges and may cause the screws to loosen or the hinges to break", causing the door to sag. The stated fix is to tighten the loosened screws, or engage a contractor for household shelter door repair to replace the broken hinges — that guide adds that household shelter accessories are only available from contractors for household door repairs, not from a hardware shop. Budget for TO FILL: typical cost to replace household shelter door hinges or repair a jammed HS door lockset in Singapore.

Ventilation openings and the 25 per cent rule

Each shelter has two ventilation sleeves capped by a 6mm stainless steel fragmentation plate, and HDB's home care guide states that during peacetime the plate is held in the open position by 4 M8 stainless steel screws connected to the sleeve, then tightened against the sleeve in an emergency to compress the "O" ring rubber gasket. Covering the openings for looks is allowed within limits: SCDF permits closing or covering them with removable aesthetic or architectural finishes only if at least 25% of the total area of the two openings is left uncovered during peacetime. Where a false ceiling outside the shelter runs below the sleeves, HDB's guidelines require perforated access panels of minimum size 600mm x 600mm positioned directly below each sleeve.

Claims the rules do not support

"Nothing may be drilled." Untrue. Shallow drilling for non-metallic inserts and removable screws is explicitly permitted, and the fixtures named in HDB's table include pictures, posters, cabinets, shelves, wall fans and ceiling lightings.

"SCDF or HDB approval is needed to renovate the shelter." HDB's building works table answers "No" in its *Permit Required?* column for every permitted household shelter work it lists, and no homeowner application route for approving a prohibited shelter work could be found on hdb.gov.sg or scdf.gov.sg. The statutory route for an alteration likely to impair the shelter is written permission from the Commissioner under section 4(1)(c) of the Act, which is not a renovation permit.

"The door can be swapped if the original is kept." Not permitted. Modifying, changing, removing or tampering with the HS door and frame appears on the prohibited list with no keep-the-original exception, and Table 8.1 of the Technical Requirements lists the household shelter door as a regulated shelter product certified under SCDF's Product Listing Scheme rather than a joinery item.

"SCDF inspects occupied flats routinely." Widely repeated in renovation forums and unverified here. No SCDF or HDB primary source describing a routine inspection regime for occupied homes could be found; what is documented is the owner's statutory duty under section 4.

Penalties and who carries the risk

Section 4(2) of the Civil Defence Shelter Act 1997 makes non-compliance an offence carrying a fine of up to $5,000, with a further fine of up to $250 for every day or part of a day the offence continues after conviction — and section 4(1) puts that duty on the owner or occupier, not only on the contractor who swung the hammer. Separately, rule 3 of the Housing and Development (Renovation Control) Rules requires an HDB flat owner to engage a renovation contractor registered by the Board, with a fine of up to $5,000 on conviction. Noble Interior Design Pte. Ltd. is listed in HDB's Directory of Renovation Contractors (DRC Ref: HB-12-5230A, UEN 201722629H) and is CaseTrust-accredited.

Ask any quoting contractor to mark the household shelter on the drawing and state which SCDF permitted works apply to it. A quotation line reading "tile shelter walls" or "replace shelter door" is not a design preference to negotiate — it is a prohibited work, and catching it at quotation stage costs nothing.