Window And Door Seals, Draughts And Noise

An apartment that is cold in winter, loud at night and dusty on the sills usually has one cause, and it is not the windows themselves.

It is the gap around them.

What a failed seal actually costs

Air moving through a gap carries three things with it.

Heat, which is why a room with a good heater still feels cold near the window. Noise, because sound travels through the smallest air path far more easily than through glass. And dust, which is why the sills on a busy road need wiping every few days.

Fixing the seal addresses all three at once, and it is a fraction of the cost of replacing a window.

Where the gaps are

The sash to frame seal. The rubber or brush seal that compresses when the window closes. It hardens, shrinks and tears over years, and once it stops compressing the window is effectively open.

Sliding door brush seals. These wear at the ends first because that is where the door parks. A worn brush seal on a large sliding door is one of the largest air gaps in most apartments.

Around the frame. The junction between the window frame and the wall. On an older building this was often filled with mortar or nothing at all, and it opens up as the building moves.

Under the entry door. A door with no bottom seal has a continuous gap the width of the door. In an apartment this also lets corridor noise and cooking smells straight in.

The test that takes a minute

Hold a piece of tissue paper along the closed edge of a window or door on a windy day. Where it moves, there is a gap.

For the entry door, look at it from a dark hallway with the light on inside. Anywhere you can see light is a gap you can feel.

What actually fixes it

Replacement seals for the sash and the sliding tracks. These are inexpensive parts and the labour is short. The difficulty is matching the profile on older windows, which sometimes means a universal seal rather than the original.

Adjustment before replacement. Many windows and doors are not sealing because they have dropped or the hardware has moved, not because the seal has failed. Adjusting the rollers on a slider or the hinges on a door often restores compression with no new parts.

Perimeter sealing at the frame to wall junction, using a flexible sealant that accommodates movement rather than a rigid filler that cracks.

Door bottom seals, either a fixed brush or an automatic drop seal for a better result at a threshold that has to stay clear.

Where noise is the priority

Seals do most of the work. Beyond that, the next steps get expensive quickly.

Heavier glass or double glazing helps, and in a strata building replacing a window is usually common property work needing approval, which changes the project entirely.

Before going there, seal everything. On most apartments the improvement is large enough that the glazing question goes away.

Condensation and the trade-off

An apartment sealed tightly with no ventilation gets damp, because moisture from cooking, showering and breathing has nowhere to go.

Sealing the draughts and then ensuring the exhaust fans actually work is the right order. Sealing without ventilation produces mould, and that is a worse problem than the draught.

Why it is worth doing between tenancies

It takes hours rather than days, it needs the apartment empty for a short window, and it is the kind of improvement a tenant notices immediately without being able to point at what changed.

We handle seals, hardware adjustment, door seals and the exhaust ventilation that has to go with them across carpentry, building and climate and air. Add it to the next round.