The useful first question is whether it changed gradually with the seasons or appeared quickly and stayed.
Seasonal movement versus real movement
Timber takes up moisture in the wet months and gives it back in the dry ones. A door that rubs along the top edge in February and clears in July is behaving normally, and shaving it in winter leaves a gap you can see all summer.
A door that binds on the latch side, has a diagonal gap, or has developed a crack in the plaster running up from a corner of the frame is a different matter — that is the opening changing shape, not the door.
The usual mechanical causes
Hinge screws pulling out of a soft frame is the most common. The fix is not a longer screw into the same hole but a plugged and re-drilled fixing, ideally reaching the stud or masonry behind the lining.
Other regulars: a lining that was never fixed square, a floor covering that has been built up under the leaf, a warped door hung the wrong way for its face, and a latch that has worn rather than a door that has moved.
- Hinge screws stripped in soft timber
- Lining out of square or unfixed at the head
- New flooring raising the threshold
- Latch and keep worn out of alignment
When to look above the door
If the frame itself is out of square and plaster is cracking diagonally from the corner, the lintel or the wall above needs assessing before any joinery. Easing the door then only masks the movement.
We'll say plainly which of the two you have on a first visit, and only recommend structural investigation when the evidence points that way.
Common questions
Should I plane a sticking door?
Only after ruling out hinge and lining problems, and preferably not in the wettest part of the year, or the door will rattle once it dries out.
Why does my door only stick in winter?
Moisture uptake in the timber. It is normal and reverses. Adjusting hinges slightly is a better first move than removing material.
Is a diagonal crack above a door serious?
It should be looked at. It can be historic settlement that has long since stopped, or it can be a lintel issue — the pattern and whether it is still moving tell you which.
Can you rehang doors without redecorating?
Usually yes for hinge and latch work. If the lining has to come out and be reset, some making good around the architrave is unavoidable.