What "dropped" actually means
On a sound commercial door, the bottom rail clears the threshold by 4–8 mm and the top of the door sits 2–4 mm below the head of the frame. "Dropped" describes any door that has lost height at the bottom pivot — usually because the pivot bearing or the closer spindle has worn. The door rotates around a lower point than it was designed for, so the leading edge swings into the threshold and the top edge drifts away from the head.
It is a mechanical fault, not a building fault. Frame movement (subsidence, vehicle impact, refurb work) can mimic the same symptoms but it accounts for fewer than one in twenty callouts — the engineer rules it out by checking frame square in the first few minutes on site.
The three pivots that wear
Most commercial entrances use one of three load-bearing arrangements at the bottom of the door: a bottom pivot (a vertical pin running through the corner of the door into a socket in the frame), a floor spring (a cassette buried in the threshold that both supports and closes the door), or a top centre paired with a bottom shoe (more common on retail shopfronts). All three wear, and all three can drop the door when they do.
The bottom pivot is the simplest — a steel pin in a brass bushing — and is the most commonly replaced. A floor spring carries more load and lasts longer but is dramatically more expensive when it fails. A top centre is the smallest part of the three and is often replaced as a preventative service the moment a customer reports drift at the top of the door.
Why dropped doors get worse fast
The door closer is the part that suffers second. A closer is tuned to bring the door home through a precise arc; when the door has dropped, that arc shortens at the latch end and the closer is no longer pulling the door against the frame as it should. The closer compensates by working harder, the hydraulic seals heat up, and the next component to fail is the closer itself — often within a few months of the original drop appearing.
After the closer, the latch and the glazing are next in line. A door that arrives late at the strike will hit it off-axis; over thousands of cycles that bends the latch tongue and chews the strike plate. A door that slams home because the closer has lost pressure shock-loads the corner joints and the glazing — which is why we sometimes find cracked corner panes on dropped doors that have been ignored for a year.
How we diagnose a drop remotely
For a same-day remote quote we ask for three pieces of evidence. First, a photo of the door at rest, taken square-on from inside the building so the line of the threshold and the line of the bottom rail are both visible. Second, a photo looking up at the transom or down at the threshold to identify whether the door runs on a transom closer, a floor spring or a simple top centre. Third, a 10-second video of the door closing from full open.
From those three pieces we can identify the failed component in roughly 95 per cent of cases. We can quote the part, the labour time, and whether the job needs an out-of-hours visit, all before an engineer leaves the depot.
The repair routes
Bottom pivot replacement is the cheapest and quickest — typically 1–2 hours on site and £200–£400 depending on the brand and accessibility. We carry universal bottom pivots that fit the large majority of aluminium-framed retail and office doors. Transom and bottom pivot repair is the relevant service silo.
Top centre replacement is similar — an hour on site, often less, and we keep stock of universal top centres. Top centre repair covers it. Top centre insert replacement (where the wear is concentrated in the plastic insert rather than the bracket) is faster again and cheaper.
Floor spring replacement is the biggest of the three. Half a day on site, a fresh threshold seal, sometimes a new cover plate, and a closer adjustment afterwards. Floor spring repair and cover plate repair describe the work in detail. The cost is typically £500–£1,000 fitted depending on brand.
When the door is not actually dropped
Two patterns mimic a drop without any pivot wear. The first is a sagging head — the top of the frame has bowed downward, often after vehicle impact or after a refurb that disturbed structural fixings. The door is square; the frame is not. Fix is structural, not mechanical.
The second is a swelled door — common on timber-framed glazed doors after water ingress. The leaf has gained thickness and is now binding on the frame rather than scraping the threshold. This presents like a drop but the engineer will spot it by checking the gap all around the door, not just at the bottom.
Maintenance that prevents the drop
A six-monthly check on a commercial entrance is enough to catch every type of drop in this article at the cheap end of the repair scale. A planned maintenance visit covers closer adjustment, pivot/top centre check, threshold inspection and a frame-square measurement. Most of our service contract customers see the cost of a single contract year covered by avoiding one emergency callout. See commercial door maintenance for the full scope.