Why Your Office Chair Is Sinking — and What Actually Fixes It

You adjust your chair to the perfect height, sit down, and over the next hour it lowers you gently towards the floor like a very slow lift with no stops. A sinking office chair is one of the most common faults there is — and one of the most fixable.

What's actually wrong

Inside the column under your seat is a gas lift: a sealed cylinder of pressurised nitrogen. The lever releases gas from one chamber to another to raise or lower the seat. When the seal wears, the cylinder can no longer hold pressure with your weight on it — so down you go. It isn't dangerous; it's just done.

The fixes, cheapest first

The clamp bodge (£five-ish). A hose clamp around the piston stops the chair sinking below the clamp — but it also stops it adjusting at all, and it looks like what it is. A stopgap, not a fix.

Replace the gas lift. Standard gas lifts are a near-universal fit — most chairs use the same taper. Separating the old cylinder from the mechanism takes some persuasion (a rubber mallet and stern words), but it's a genuine repair.

Rebuild the whole underside. If your chair is sinking and wobbling and the wheels have gone crunchy, our complete chair bottom refurbishment kit (£52.99) replaces the base, gas lift and castors in one heavy-duty go. If the seat itself is still comfortable, this is dramatically cheaper than a comparable new chair.

When to check the mechanism instead

If the chair isn't sinking but leaning or stuck reclined, the fault is usually the tilt mechanism plate rather than the gas lift — see our tilt & lock mechanism (£17.99) and measure your bolt spacing (150 × 255mm is the common standard).

Repair or replace?

Our rule of thumb: if the seat and back still support you comfortably, repair. The underside of a chair is plumbing — replaceable. The upholstery is the part worth money. Email a photo of your patient to info@chairoutlet.co.uk and we'll diagnose it for free.