A friction stay carries the sash, sets how far it opens, and holds it at any position through friction in the tracks. Get the size wrong and the sash drops, binds, or will not stay put in wind.
Start with the sash weight
Every stay has a load table — maximum sash weight against stay length. Weigh the sash properly: a 1.2 m × 1.2 m double-glazed aluminium sash is often 22–28 kg, more with laminated glass. Pick a stay rated comfortably above that, not at the limit.
Then the length
As a starting point, the stay length is roughly two-thirds of the sash height for a side-hung window, then confirmed against the manufacturer’s chart for the weight. Too short and the sash sags at full open; too long and it fouls the frame.
Side-hung or top-hung
- Side-hung stays hinge on the vertical edge; the window opens like a door. Handle sits on the opposite stile.
- Top-hung stays hinge along the top; the window projects out at the bottom, good for rain protection and for openings above worktops.
The opening direction and where the handle lands usually decide it — send the elevation.
Egress and easy-clean stays
An egress (fire-escape) stay lets the sash swing almost flat for escape or cleaning from inside. Codes and many commercial clients require egress on habitable upper floors. An easy-clean stay has a slide that frees the sash to rotate for cleaning the outer face. Decide this before you order — the geometry is different.
Common mistakes
- Sizing to sash height alone and ignoring the glass weight.
- Fitting one stay where the width needs a pair.
- Mixing brands of stay and lock so the throw does not line up.
Tell us the sash size, the glass build-up and whether you need egress, and we will confirm the stay from stock.
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