Can you drill into the bomb shelter wall?

Bomb shelter drilling: what is allowed?

The Singapore Civil Defence Force (SCDF) sets out the rules in its list of permitted and not permitted works for household shelters. It allows one kind of drilling: into the internal face of the shelter walls and ceiling slabs, to a depth of not more than 50mm, to fix inserts and removable screws. Fixtures on the internal face, such as pictures, posters, cabinets or shelves, must be removable. If you are notified, you must take them down within 48 hours. Non-metallic inserts may be any diameter as long as they are no longer than 50mm, and it is up to you to make sure each insert is strong enough for what it holds. Power-driven nails are allowed only on the external face of the shelter walls, no longer than 75mm, and not into the internal walls.

HDB's renovation guidelines for building works say the shelter's reinforced walls, floor slab, ceiling and steel door must not be tampered with. They set the same limit: drilling into the internal walls is limited to 50mm deep for non-metallic inserts and removable screws, and fixtures there must be removable within 48 hours when notified.

Before you drill a shelter wall, check that every hole will stay within 50mm and every fixing can be unscrewed later.

What is not allowed

SCDF's works list starts from a firm rule: the shelter's walls, floor, ceiling and door must not be hacked or drilled, and works likely to weaken or damage its structure are not permitted. The shallow drilling described above is the one exception. Inside the shelter, the list does not permit:

• wall tiles, rock tone, cement sand or gypsum plaster on the internal walls
• floor tiles laid with adhesive
• a second layer of tiles
• cornices
• indiscriminate hacking, or drilling beyond the permitted drilling
• hacking to form a key for tiling

For the household shelter, HDB rules are just as firm. According to its household shelter care guide, HDB has equipped every flat with a household shelter since 1996. The shelter has strengthened walls, floor and ceiling and a specially designed door, and these must not be hacked or drilled beyond the shallow drilling described above. HDB explains that certain finishes and fixtures are not permitted because they cannot be easily removed and may become hazards in an emergency.

Painting and the shelter door

You can paint the shelter walls, ceiling and door, as SCDF's works list permits painting. The limits are around the door and the vents. Never cover or paint over the shelter door notice, the locking bolts or the door seal, and do not tamper with, remove or cover the door notice. Do not modify the door, its frame or the ventilation openings, plates, bolts or nuts. Removable finishes may cover the ventilation openings only if at least 25% of the two openings stays uncovered.

HDB's household shelter care guide explains that the door gives an air-tight closure, and the rubber gasket at the door and ventilation sleeve keeps the shelter air-tight. Its door care tips:

• Hold the handle when you open the door, so it does not hit the skirting tiles. That stresses the hinges and can make the door sag.
• Oil the movable parts, such as the latch, hinges, locking bolts and handle.
• Keep water out of the lockset when cleaning, and wipe it dry afterwards.
• Check the ventilation sleeve regularly so its "O" ring gasket stays intact and its screws stay oiled.

Shelving and storage ideas

Most storage needs in a shelter can be met within the rules. A freestanding rack needs no drilling at all. If you want wall shelves, choose removable shelves fixed with screws or inserts in holes no deeper than 50mm, so they can come down when needed. Keep heavy loads on the floor or on freestanding racks rather than on wall-mounted shelves.

If you have a new BTO flat, the MyNiceHome move-in guide notes that a set of sample anchors is provided in the household shelter for wall fixtures. It also advises avoiding areas with concealed electrical wiring when you install anchors. For shelves in the rest of the home, see the guide to shelf installation.

Hiring a handyman

Tell the handyman that the wall belongs to the household shelter before any drilling starts, and agree on hole depth and removable fixings first. For walls elsewhere in the flat, read the HDB drilling rules guide before work begins. The price depends on the job, so compare handymen and their published prices for the same scope of work.

Shelter door repairs are a separate job. HDB's household shelter care guide says shelter door accessories are only available from contractors for household shelter door repairs. Engage one for broken hinges or a lockset that lubricant does not free.

Questions