Why a door sticks in summer and not in winter

What you notice, and the order it comes in

A dropping door warns you in the same order every time. Most people are three steps in before it counts as a problem.

Whether it is worse than last year is the part that decides it. A door with nothing wrong but summer behaves the same every year. One that sticks earlier each spring has been dropping all along, and summer is just when it runs out of gap.

• It needs a push at the end of a swing that used to fall shut.
• One point in the swing bumps and releases: the top corner meeting the frame.
• A shiny, paint-worn band at the top of the latch edge, and a bright arc on the strike plate below its opening.
• You start lifting the knob without noticing, which puts the bolt level with its hole.
• It stops latching in the humid months, frees up in the fall, then sticks earlier the year after.

Swelling and sag leave different gaps

Close the door and look at the line of light around it: what matters is whether it is the same width top to bottom. A swollen door still hangs true, so the lines stay parallel. A sagged door does not, and its latch-edge gap closes at the top and opens at the bottom.

Grip the knob, lift, and push the door shut. If it latches when you lift and refuses when you do not, the bolt is arriving below its hole. That is sag. Then close the door on a strip of paper and pull it out at the top, middle and bottom of the latch edge: where it grips is where the door is really touching.

• Grip at the top of the latch edge only, with a latch that needs lifting: the hinges dropped.
• Grip evenly the whole way down, gap lines still parallel: seasonal swelling.
• Grip on the hinge side too: the door is hinge bound, which is paint rather than moisture.
• Doors and windows along one wall tightening together, casing miters opening: the opening moved, not the doors, and the cause is under the house.

Why the top hinge is the one that gives

A jamb is not part of the structure of the house. It is a light board held off the framing on shims with air behind it, and the screws in the hinge box are about three quarters of an inch long, enough to bite that board and nothing beyond. The door's whole weight hangs on those, in softwood pine, and an older jamb has usually had the same screws back in the same holes more than once.

The hinges do not share that weight evenly. The bottom one is pushed into the jamb and the top one is pulled out of it, so the top works loose first. Its holes go oval, the leaf tips away by a fraction, and the latch edge drops several times that, because the door is a long lever and the hinge is the short end. Press the top leaf toward the jamb with your thumb while somebody swings the door. Movement there is the fault, whatever the weather is doing.

What summer actually does to wood

Wood moves across the grain and almost not at all along it. A panel door is vertical stiles and horizontal rails with panels floating loose in grooves, precisely so the movement gets broken up: across the width, only the two narrow stiles can grow.

How the door is made decides whether swelling is on the table. A hollow core interior door is two thin skins over a cardboard lattice and does not meaningfully swell, and neither do steel or fiberglass, so a sticking door of any of those three is hinges, paint or the opening. Solid wood is where swelling is a real answer, and it lands on the edges nobody finishes: the top and bottom are cut on site and left bare, and bare end grain drinks far faster than a painted face.

The floor under an interior door also lifts a little through a wet summer, which is a crawlspace question more than a door one. A door tight through the humid stretch, free the rest of the year and no worse than last year is not broken.

Why planing comes last

Rule the paint out first: coat after coat inside the hinge mortises pushes the door across the opening toward the latch side, and stripping a mortise back to bare wood is sometimes the whole repair. Planing is the other instinct, and the only step here you cannot undo. Cut a door to fit in August and you have fitted it at its largest size of the year, so by January there is a gap you can see daylight through. It also opens bare wood along the cut, which drinks faster than a finished edge. And if the hinges were the fault, planing does not touch it: the latch is still landing below the strike.

Most of this is a screwdriver and twenty minutes

A dropping door is homeowner work. Try every screw in the top hinge: any that spin without pulling tight have found the problem.

Take out the screw nearest the door stop and put a three inch screw in its place, driven through the jamb, across the shim gap and into the framing behind. Snug it a little at a time, watch the gap at the top of the latch edge close, and stop when it looks even: pulling the jamb in too far bows it the other way.

If the hole is worn enough that even a long screw spins, pack it: glue and a few bamboo skewers or a golf tee, tapped in and trimmed flush, give the screw fresh wood to bite. If the door then hangs straight and the latch still misses, the strike plate is the answer, not the door.

Where to stop: a jamb soft at the bottom, an exterior door dropped far enough to need rehanging, an opening that has moved, and any door already planed. Door hardware that has to be wired in is its own trade rather than part of this work.

So does it need doing

The hinge screws are worth doing now whatever else is true. The door only drops further while it waits, wearing its own latch edge and chewing the strike plate.

A door that binds lightly, latches without a lift, and is no worse this year than last can wait indefinitely. Judge it in November: if it closes cleanly then, nothing is wrong with it.

Now, without waiting: an exterior door that will not latch or lock, since that is security and weather at once, and a jamb gone soft at the bottom, since that is water getting in.

Soon rather than now: several doors binding at once alongside cracks at the casing corners or a floor that gives underfoot. That cause is not in the jamb.

The one thing not to rush is planing. A door that genuinely needs material off needs it off in the driest part of the year, sealed the same day. In August, hold off.

Questions that come with this one