Ever walked into a resale HDB and wondered why there’s a random hole in the wall or a random spare room at the back of the house? These oddities often confuse younger homeowners, but they’re actually remnants of an era when Singaporean homes were built very differently.
From mysterious wall cavities to double-entrance kitchens and old letterboxes, many of these “strange” features weren’t design flaws, but practical solutions shaped by the lifestyles, technology, and public housing priorities of earlier decades.
Here are some of the quirkiest old HDB features still found in resale flats today.
1. Hole in the wall
Image credit: jojo_chinny
If you’ve ever viewed an older resale flat, you might have noticed a strange rectangular hole near the bedroom window. This wasn’t damage or a botched renovation. It was actually a dedicated slot for old-style air-conditioning units, which were installed as one bulky piece that sat directly inside the wall opening.
Back then, split-unit aircons didn’t exist, so the only way to cool a room was to carve out a space for these all-in-one compressors. The unit would stick halfway inside the flat and halfway outside, practical for the time, but leaving behind an awkward reminder of how things have evolved.
Today, modern split-unit systems use a slim indoor fan coil paired with an outdoor compressor, making these original wall openings unnecessary. But because many flats built before the 1990s came standard with these aircon cavities, resale units often still have them.
In case you are wondering where to find them, you’ll typically see them in pre-1990s flats, like Blocks 1 to 12 in Toa Payoh Lorong 6.
2. Kitchens with two entrances
Image credit: PropertyGuru
Step into a resale flat from the 1970s to early 1990s, and you might be surprised to find a kitchen with two entrances. One opens into the dining area, while the other leads out to the living room.
Interestingly enough, there are other older ground-floor or first-storey HDB units that had a “service entrance” or back door. This secondary access point served several practical purposes:
- Gas delivery: Before piped gas was common, delivery personnel would bring gas canisters directly to your kitchen through the back door.
- Groceries and milk delivery: Vendors could drop off daily necessities without walking through the main living space.
- Helpers’ access: Households with live-in helpers often preferred a more discreet entryway for household tasks.
As privacy and security standards evolved, and as service deliveries disappeared, HDB phased out the dual-door layout. Modern flats now feature a single consolidated kitchen entrance, creating a cleaner, more efficient interior flow.
But in a few rarer older resale units, that second kitchen door still exists, often sealed up or repurposed.
3. Lack of bomb shelters
Image credit: The Interior Lab
While newer BTO flats come with a standard bomb shelter, older resale flats don’t. This is because bomb shelters simply didn’t exist in flats built before the late 1990s, allowing for larger kitchens and more open entryways.
HDB only started including Household Shelters (HS) from 1998 onwards, following the introduction of the Civil Defence Shelter Act. This shift was influenced by global events, particularly the 1991 Gulf War, which highlighted the need for safe, reinforced spaces in homes due to the impact conflicts could have on civilian areas.
Before this change, families relied on community shelters or public buildings in emergencies. As a result, older flats were designed without the reinforced concrete space we now recognise as bomb shelters.
The introduction of bomb shelters significantly changed the storage and layout of modern units:
- It is the only room in the house you’re not allowed to hack or structurally change.
- It often doubles as a storeroom, with most households using it to stash luggage, tools, or bulky items.
4. Breeze blocks for better ventilation
Image credit: Darren Soh
Older HDB flats often featured small vents or patterned breeze blocks above doors and in kitchens and even at the staircase landings. Before air-conditioning became common due to the high costs, these openings helped air flow through the home naturally, keeping spaces cooler and reducing humidity.
They were eventually phased out due to fire safety rules, pest issues, and improved ventilation thanks to ceiling fans and more affordable air-conditioning that made open gaps unnecessary. Modern layouts also value privacy and noise control, which breeze blocks didn’t provide.
Image credit: Free Space Intent
Yet, what was once a basic functional feature is now enjoying a revival. Many homeowners renovating older flats are reintroducing breeze blocks as decorative partitions, entrance screens, or feature walls, giving their homes a retro, airy touch with a nod to Singapore’s past.
5. Utility rooms
Image credit: 123home, U-Home Interior Design
In many early HDB flats, especially those built before the 1990s, you’ll often find a small dedicated utility room tucked near the kitchen or service yard. Depending on the household, this space was sometimes used as a “maid’s room,” “granny room,” or general storeroom, giving families extra functional space in an era when flats were designed with more practical, task-oriented layouts.
Turned into a hybrid study-and-gaming zone.
These rooms were incredibly versatile, used for storing bulky household items, or as an extra sleeping area for extended family or live-in helpers.
As home layouts evolved and modern safety requirements came in, these utility rooms gradually disappeared. They were replaced by either:
- Bomb shelters introduced from 1998 onwards
- Larger, more open kitchen layouts that combine cooking, laundry, and utility functions into one big space
6. Old-style letterboxes
Image credit: irememberSG
If your grandparents lived in an HDB, you might have noticed rows of very tall metal letterboxes lining the void deck walls.
Unlike modern blocks with mailboxes that come with existing locks, these old-style letterboxes were lock-less. Residents had to bring their own padlocks to keep their mail safe, leaving unlocked letter boxes vulnerable to theft.
Today, HDB has standardised mailbox systems in new and upgraded blocks. These centralised units allow mailmen to deliver letters efficiently using a master key, feature small lockable slots to keep unwanted flyers out, and can even be upgraded with digital locks for added security in some cases.
7. Flat with two entrances
@our_home_matters HDB with 2 entrances. #fyp #sgtiktok #HDB #singapore #BTO
♬ original sound – isaacyeeyc – Isaac Yee (余衍昌), Trusted Agent
Another feature you might notice in older resale HDBs is 2 entrances into a home. This wasn’t a strange design experiment, it existed because older blocks originally had lift access only on selected floors and not every level.
Back then, lifts only stopped at selected levels, typically level 1, 6, 12, and so on. If you lived on a floor in between, you had to take the lift to the nearest landing and then climb a flight of stairs to reach your flat.
When HDB upgraded lifts to stop at every floor, some units ended up with two entrances with the original main entrance connected to the corridor or stairway and the second entrance opening directly to the newly created lift lobby.
For homeowners today, these dual entrances can be puzzling or even impractical, but they are a direct reminder of how HDB adapted older buildings to meet accessibility needs.
Quirky HDB resale features explained
These quirky HDB resale features may seem outdated today, but they were once perfectly normal, from old-school aircons to the minor frustrations of too much junk mail.
Understanding these design quirks not only helps resale homeowners appreciate their flat’s history, but also highlights just how much Singapore’s public housing has evolved over the decades.
In for nostalgia? Check out these articles:
- HDB blocks that no longer exist
- 7 nostalgic HDB features worth reviving
- Why I’ll never forget growing up in and old 3-room HDB
Cover image adapted from: PropertyGuru, jojo_chinny
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