A door that sticks or drags on the floor is almost always a hinge or frame alignment problem, not a sign the door itself has grown or changed shape — the door has usually dropped slightly on worn hinges rather than the door being the wrong size.
Doors are heavy, and they hang entirely on their hinges. Over time, hinges wear, screws holding them can work loose in the frame, and the door gradually drops on the hinge side — often by only a few millimetres, but enough to catch on the floor or stick against the frame on the opposite side. This is why an exterior door that closed perfectly for years can start sticking without anything obvious having changed.
Timber doors and frames can also be affected by seasonal moisture changes, swelling slightly in damp weather and shrinking back in dry conditions, which can make sticking worse at certain times of year even with sound hinges.
Tightening or replacing worn hinges, and correcting the frame alignment where needed, resolves the great majority of sticking or dragging doors. Full door or frame replacement is usually only needed where there's actual rot or structural damage, which is a different (and less common) problem from ordinary hinge wear. This is one of the most frequent repair call-outs we get from homes across Preston and Lancashire, since every exterior door takes daily use.
GreenFix provides door repairs across Preston and Lancashire. From £65 (guide price only, confirmed after assessment).