Top hung windows are the most common opening window in South African homes, and the reason is weather. The sash is hinged along its top edge, so when it opens the bottom swings outward and rain runs off it instead of into the room.
How top hung windows work
A pair of friction stays is fixed along the head of the frame and the top of the sash.
When you release the handle, the sash pivots on those stays and the bottom edge travels outward.
Friction in the stay holds the sash wherever you leave it. There is no prop or catch to set.
That is the whole mechanism, and it is why top hung windows have so little to go wrong compared with a sliding sash running in a track.
Where they suit a room
Bathrooms are the obvious case. A top hung sash can be left cracked open in light rain for ventilation without water coming in.
Bedrooms benefit for the same reason, particularly for night ventilation when nobody is awake to close up if the weather turns.
Above a kitchen counter they open away from the worktop rather than over it, so nothing has to be moved to reach the handle.
On upper floors, no sash swings inward across the room, which matters where furniture sits under the window.
Top hung windows compared with sliding windows
A sliding window gives you at most half the opening, because one panel has to pass behind the other.
Top hung windows open the full width of the sash, and you control the angle rather than the width.
Sliding windows also run in a bottom track, which collects grit and needs cleaning. A hung sash has no track at all.
Against that, a sliding window projects nothing outside, which matters on a narrow walkway or against a boundary wall.
What to decide before ordering
First, how much of the opening should actually open. A common arrangement is a top hung sash over a fixed light, which keeps the glass area up without adding a second moving part.
Fixed lights cost less than opening sashes because they carry no hardware, so put the opening where you will use it.
Second, the finish. Powder coated or anodised, decided at order stage because the finish goes on the profile before the window is made up.
Third, the glass. Standard glazing is 6.38mm clear laminated safety glass.
Measuring for top hung windows
Measure the structural opening, brick to brick, in millimetres. Take the width in three places and the height in three places, and work to the smallest figure in each.
Our measuring guide covers the method, and aluminium window sizes explains how sizes are written down.
You can browse by dimension using shop by size, or see the full aluminium windows range.
Coetz supplies aluminium windows and doors nationwide across South Africa. We do not install; fitting is arranged by you. For glazing standards, SAGGA, the South African Glass and Glazing Association is the industry reference body.
Maintaining top hung windows
There is very little to do, which is the point of them.
Wipe the friction stays and the frame rebate twice a year. Grit and paint build-up between sash and frame is the most common reason a sash stops closing cleanly.
Check that both stays travel evenly. If one moves further than the other, the sash meets the seal crooked and draughts follow.
Wash the frames with clean water and a mild detergent. Powder coated aluminium needs no repainting, and abrasive cleaners will dull the finish.
Replace the compression seal when it hardens. It is a cheap part and it is what keeps the window airtight.
What top hung windows cost to run
Nothing, in the ordinary sense. There is no repainting cycle, no track to replace and no motor.
Over a twenty year life the only consumables are seals and, occasionally, a stay.
That is the practical argument for aluminium over steel or timber: the running cost of the frame is close to zero.
Combining sashes and fixed lights
Most frames are not a single sash. They combine top hung windows with fixed lights in one frame.
A wide opening might have two top hung sashes side by side over a continuous fixed light below.
A narrow one might be a single sash with a fixed pane beneath it.
The split is yours to choose at order stage, and it is the main lever on price.
Frequently asked questions
Do top hung windows let rain in?
Less than most alternatives. The open sash leans outward, so water runs off it away from the opening.
Can top hung windows be used as a fire escape?
That depends on the opening size and the regulations applying to your building. Check the required escape dimensions before specifying.
How far do top hung windows open?
As far as the friction stay allows, and they hold at any angle within that range.
Are top hung windows easy to clean?
The outer face is reachable from inside on most sizes, because the sash swings clear of the frame.
What glass is standard?
6.38mm clear laminated safety glass.
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