A door closer that is too weak will not latch the door; one that is too strong slams it and makes it hard for anyone to open. Closers are graded by power size (EN 1154, size 1 to 7), set mainly by the door leaf width.
Match the power size to the leaf width
As a guide:
- Up to ~850 mm leaf: size 2–3
- 850–950 mm: size 3–4
- 950–1100 mm: size 4–5
- Over 1100 mm or heavy: size 5–6, or an adjustable size 2–5 closer wound up
Adjustable-power closers (EN 2–5 or 3–6) cover most doors and let you tune on site — the safe default for a mixed job.
Step up a size for exposed doors
A main entrance that catches wind, or a door on a pressurised lobby, needs more closing force to overcome the draft. Go one power size above the width table, and specify backcheck so the wind cannot fling the door open and damage the hinges.
Features worth having
- Backcheck: cushions the door near full open. Specify on every external door.
- Delayed action: holds the door open for a few seconds then closes — useful at accessible entrances and where people carry loads.
- Adjustable latch speed: separate control for the last 10–15° so the door latches without slamming.
Fixing matters
On a hollow aluminium door, use the closer maker’s fixing plate or a through-bolt — self-tappers into a single skin pull out. On a glass door, that means a patch or a floor spring instead (see the glass hardware guide).
Send the leaf width, weight, whether it is external and which way it opens, and we will spec the closer.
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