A front door that sticks, drops or stops locking has almost always moved rather than broken. Hinges settle under the weight of the door, and the lock stops meeting the keep. Most of it is an adjustment rather than a repair, and on a uPVC or composite door you do it with an Allen key.
Close the door slowly and watch where it touches. The point of contact tells you which way the door has gone, and that decides which adjustment you make.
That last one matters. Planing a timber door that sticks in January leaves you with a gap in July, and it cuts through the paint seal that was keeping water out in the first place.
Both use the same style of adjustable hinge, and both adjust in three directions. You need a set of Allen keys and a screwdriver, and the whole job takes about twenty minutes.
Find the adjustment points. Most hinges have a cap or a cover that lifts off, revealing two or three grub screws. One controls height, one controls lateral position, one controls compression against the seal.
Adjust in small increments. A quarter turn moves the door more than you expect. Turn, close the door, look, turn again. Chasing a problem with big adjustments means overshooting it in the other direction.
Work top hinge first for lean, all hinges together for height. A door leaning out at the top is a top hinge adjustment. A door that has dropped needs all the hinges lifting by the same amount.
Check the lock last. Once the door sits right in the frame, try the handle. If the bolts throw cleanly, the job is done. If they still catch, the keeps in the frame need moving rather than the hinges.
Timber hinges rarely adjust in the way uPVC hinges do. You move the hinge or the keep instead.
A dropped door usually means the screws in the frame leaf have loosened in their holes. Take them out, glue a hardwood dowel or a couple of matchsticks into the hole, let it set, and screw back into solid timber. Longer screws that reach the frame behind the lining hold better than the originals.
A door that binds on the hinge side has hinges set too deep. Pack behind the hinge leaf with a thin card or veneer shim.
A door that binds on the lock side has hinges not deep enough, or the door has swollen. Deepen the hinge rebate before you consider planing anything.
A door that will not latch needs the keep or the strike plate moving rather than the door. Slacken the screws, shift it a millimetre or two, retighten and test.
Most external door handles come off with two screws through the inside plate, and the spindle pulls through with them.
Measure before you buy a replacement. Three figures decide whether a handle fits: the centre distance between the two fixing screws, the distance from the spindle to the keyhole, and the backset from the door edge to the spindle. A handle sold as a like-for-like replacement will list all three.
Take the old handle off and take it with you, or photograph it against a tape measure. Handle plates are made in several standard patterns and they are not interchangeable.
On a modern multipoint door you change the cylinder rather than the lock. The cylinder is the barrel the key goes into, it comes out on a single screw through the edge of the door, and it is the part that fails or gets upgraded.
Measure the cylinder. Take it out and measure each side from the central fixing screw. A cylinder is quoted as two figures, for example 40/50, and getting it wrong by 5 mm leaves it either recessed or protruding. A protruding cylinder is a security problem in itself.
Note the type. Euro profile, oval and rim cylinders are different formats and do not substitute for each other.
Consider what you are buying. Cylinder ratings exist for a reason, and a cylinder change is the cheapest security upgrade available on any door. If you are replacing one anyway, replace it with a better one.
Most of the problems above come from water getting into timber or from hinges carrying a load they were not adjusted for. Both are cheaper to prevent than to fix.
Pine doors. Check the surface once or twice a year, and look hardest at the elevations that get the most sun, because sunlight is what breaks paint down. Recoat when the surface starts to dull rather than waiting for it to flake, and pay attention to the top and bottom edges, which are end grain and take in water fastest.
Alu-clad pine. Wash the frame and the door face a couple of times a year with pH neutral soap and lukewarm water. That is the whole routine on the outside face.
uPVC. A damp cloth on the frame and the face. Keep the drainage slots at the bottom of the frame clear, because a blocked slot holds water against the seal.
All three. Put a drop of light oil on the hinges and the lock mechanism once a year, and check the seal for splits at the same time. A perished seal is a five minute replacement and the commonest cause of a draughty door that adjusts fine.
