Sliding or casement windows: which suits an HDB flat?

Sliding vs casement window at a glance

Neither type suits every HDB flat; it depends on the room. Casements fit where you want the full opening and a firm seal, such as a bedroom that catches the evening breeze. Sliders fit where an outward swing would clash, like a kitchen window beside the laundry pole holders.

The bigger difference shows up in upkeep. A casement depends on small metal parts at its stays, while a slider depends on a clean track and two safety parts. The last row of the table follows BCA's window checklist. Quick answers on fittings sit in the windows and doors FAQ.

Casement windows in HDB flats

A casement window HDB residents open each day swings on hinges, pivots or friction stays, as HDB's windows guide describes the type. HDB says casement windows that do not comply with retrofitting requirements must be retrofitted with stainless steel rivets, and there are penalties if a window falls through lack of maintenance or an owner fails to retrofit. Windows in flats on the lowest level are exempt from BCA's Building Control Regulations. In the retrofit, BCA says approved window contractors replace all aluminium rivets at the casement window stays with type 304 stainless steel rivets.

You can check the panels yourself. BCA's checklist suggests a mirror to see the screws and rivets on the upper edge and underside of each panel. Look for rivets that are broken or corroded, screws that are loose or rusty, and friction stays that are bent or loose. A handle that no longer pulls the panel snug needs attention too. The window safety inspection guide sets out a fuller routine.

Sliding windows in HDB flats

Every sliding window HDB owners look after has a short parts list: the panels, the rollers they ride on, the track and two small safety parts. BCA's checklist asks you to check that the safety stopper and angle strip are in place and that the panel slides smoothly.

In a flat beside an MRT viaduct or a construction site, fine grit and corridor dust pack into the track corners. Vacuum the track with a narrow nozzle, then wipe it with a damp cloth. Never lift a panel off its track to clean behind it, and never force one that drags. If a panel sticks, the sliding window stuck guide walks through the likely causes.

Rain, noise and seals

A casement keeps rain out by pressure: turning the handle pulls the panel tight against a rubber seal. A slider cannot clamp shut that way, because its panels must still glide, so it relies on brushes and seals along the track and where the panels overlap. When a Sumatra squall drives rain sideways, worn brushes on a slider can leave water on the sill.

Seals harden and crack with sun and age. A seal that feels brittle or has gaps at the corners lets in water and more corridor and traffic sound. The window rubber seal guide explains how to tell when one needs changing. If your slider's track has small drain slots, keep them clear so water can run out.

Grilles and child safety

A casement swung wide leaves the whole frame open, while a slider leaves half of it. Either gap can be enough for a small child, so the window on its own is not the safeguard.

Keep beds, sofas, shoe cabinets and toy boxes away from windows so they cannot become steps, and close and lock panels when children play nearby. Grilles add a physical barrier. Before choosing a design, ask the installer how it affects opening and cleaning your panels, and check with HDB whether anything applies to your block. The comparison of invisible grilles vs traditional sets out how the two designs differ.

Changing window type

Swapping casements for sliders, or the reverse, is window replacement. HDB's window works guideline says all window installation or replacement work must be done by a BCA Approved Window Contractor (AWC) listed in HDB's directory, and a renovation permit from HDB is required for all window replacement work. The AWC applies for the permit. HDB also says flat owners and occupants are responsible for the upkeep of their windows.

Ask how the new frames will cope with rain on your facing, and how the outer panes can be cleaned from inside. Quotes depend on the job, so set them side by side, window by window. HDB's guideline lets you add film to window glass without a permit, provided it is non-reflective or within a reflectance limit. The HDB window replacement rules guide covers the process in more depth.

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