Sticking doors appear on every list of subsidence warning signs ever published, always as a bullet point and never with an explanation. That is unhelpful, because the great majority of doors that stick are not telling you anything about the structure at all - and the ones that are can be identified by a distinction almost nobody makes.
The distinction is this. Seasonal movement reverses. Structural movement does not.
Why timber doors stick, most of the time
Timber is hygroscopic - it takes up moisture from the air and gives it back, and it changes dimension as it does. In a damp autumn a timber door swells and starts to catch. In a dry heated winter, or a dry summer, it shrinks back and the problem disappears.
This is why so many people notice a sticking door in October and find it fine by February. It is also why a door that was eased with a plane during a wet spell then rattles for the rest of its life. If your door binds at the same time each year and frees itself again, that is moisture, not the building.
The other everyday causes are just as undramatic: hinges dropping or screws loosening, a door that has never been hung well, paint build-up over decades, swollen or lifted flooring, and carpet or underlay fitted thicker than the clearance allowed for.
When a sticking door is telling you something
A door binds structurally when the frame it sits in is no longer square - because the wall around it has moved, or the floor beneath it has dropped, or a lintel above it has deflected. The markers:
- It binds in one specific corner consistently, rather than along a whole edge - a squareness problem rather than a swelling problem
- The gap around the door is visibly tapered, wider at one corner and closed at the diagonally opposite one
- It has got progressively worse over years, and it does not free itself in dry weather
- It has been eased more than once - each easing is a dated record of movement, and two or three of them is a movement history
- Several doors and windows in the same part of the house have gone at the same time
- There is corroborating evidence: fresh cracking, a floor that slopes towards the same corner, a crack above the opening
- The frame itself is visibly distorted, or the glazing in a window has cracked without impact
What you can check yourself this week
This is a defect a homeowner can gather genuinely useful evidence on, and it costs nothing:
- Note the date and the weather. A door that started sticking in a wet October is a different case from one that started in a dry July.
- Look at the gap all the way round. Even gap that has simply closed up means swelling; a tapered gap means the frame is out of square.
- Measure the two diagonals of the door frame with a tape. If they differ, the frame is not square, and by how much.
- Check the floor with a spirit level in the doorway, in both directions.
- Look at the head of the opening for cracking, and at the wall above it.
- Test the same door again in three months and write down what you find. That two-line record is worth more to an engineer than any single observation.
When to call an engineer
A threshold rather than a plea. A single door that binds seasonally and frees itself does not need an engineer; it needs a plane, and preferably in the damp season so you do not over-take it. Get it inspected if the frame measures out of square, if several openings have gone at once, if the binding is progressive and does not reverse, or if it comes with fresh cracking or a floor that has dropped.
And if you are buying a house where doors have plainly been eased more than once, that is worth asking about. It is not proof of anything, but it is a dated record that somebody has been managing a symptom for a while.
How we would investigate it
By treating the door as one piece of evidence rather than the diagnosis. Squareness of the openings, floor levels across the room and the building, classification of any associated cracking against the BRE Digest 251 categories, and the search for corroboration that separates a building that has moved from a door that has swollen. Where it is not resolvable in one visit, monitoring across a full seasonal cycle answers it with measurement.
The most common outcome is a written confirmation that the movement is historic and the building is stable, which is precisely the document a buyer or a lender needs. We do not carry out repairs and take no commission from anyone who does. A structural survey and report is a fixed £580 + VAT, report inside 10 working days of the inspection, guaranteed.
Frequently asked questions
Do sticking doors mean subsidence?
Almost never on their own. Timber swells in damp weather and shrinks in dry, so a door that binds in autumn and frees itself in spring is telling you about humidity, not the ground. What points at structure is binding that is progressive, does not reverse, affects one corner of a frame that measures out of square, and comes with corroborating evidence elsewhere.
How do I tell the difference myself?
Two checks. Look at the gap around the door: an even gap that has closed up is swelling; a tapered gap, wide at one corner and closed at the opposite one, means the frame is out of square. Then measure the frame's two diagonals - if they differ, something has moved. Write down the date and the weather while you are at it.
Several doors upstairs have started sticking at once. Is that a concern?
It is more of a concern than one door, and worth having looked at - but it can still be seasonal, since all the doors in a house experience the same weather. The useful questions are whether they free up again in dry conditions, whether the frames measure square, and whether anything else in the same part of the house has changed.
Should I just plane the door?
If it is seasonal, yes - but do it in the damp season, or you will take off too much and have a rattling door for the rest of the year. If the frame is out of square, planing it hides the evidence without addressing anything, and you may end up doing it again.
The doors were eased by the previous owner. Does that matter?
It is worth knowing about. Each easing is a dated record that somebody was managing a symptom, and two or three of them over the years is a movement history rather than a one-off. It is not proof of a problem, but it is exactly the sort of thing an engineer wants to know at the start of an inspection.