A bedroom door that used to click shut now kisses the strike and bounces back. A bathroom door scrapes a quarter-moon into the paint. The hall door drifts open two inches whenever the furnace kicks on, as if the house were exhaling it out of the way. None of that usually means you need a new slab. It means the rectangle of the door and the rectangle of the jamb have stopped agreeing.
Interior doors are light, hollow, and honest. They show hinge sag, seasonal swell, and a strike plate that was never quite where the latch wanted to land. The repair is almost always geometry, not shopping.
Watch the Door Before You Take It Off
Close it slowly from several angles. If the latch hits high or low on the strike, the slab has dropped or the jamb has shifted. If it hits the front of the plate and will not go in, the door is proud of the jamb or the plate is too shallow. If the top latch-side corner rubs the head jamb, the hinge side may have pulled out of the stud or the top hinge screws are spinning in dust.
A door that swings open by itself is rarely haunted. The jamb is out of plumb, the hinges are not in the same plane, or the house simply leans a little and gravity is doing the rest. Stand at the edge and look down the face. A gap that is wide at the top on the latch side and tight at the bottom is a dropped door. A consistent rub along the latch edge in late summer is often humidity.
Hinges Do Most of the Talking
Three hinges share the weight. The top one takes the worst of the cantilever. Short screws into a hollow jamb are how that hinge loosens. Pull one screw from the top hinge on the jamb side and replace it with a three-inch screw that bites the framing. Do the same for a second screw if the door still droops. You are not trying to crank the door into a new building. You are pulling the hinge leaf back to the stud so the slab rises a fraction and the latch meets the hole again.
Bent hinge pins and worn knuckles show up as a door that sags even after the screws are tight. Swapping a tired hinge for a matching one is cheaper than planing a door you will then have to paint. Keep the same corner radius and the same screw pattern or you will be filling holes for an afternoon.
If the door binds at the top latch corner after you tighten the top hinge, the bottom hinge may need a thin cardboard shim behind the jamb leaf to tilt the slab back. Small shims. Test after each one. This is easier than removing a sixteenth of wood you cannot put back in January.
The Strike Plate Is a Small, Honest Part
Sometimes the door height is fine and the latch still does not catch because the hole in the plate is a hair too high, too low, or not deep enough. Outline the current plate with a pencil. File the opening a little in the direction the latch wants to go, or shift the plate and extend the mortise with a sharp chisel. A latch that only just kisses the plate will vibrate open when someone walks past.
Privacy and passage latches fail in their own dull ways. A spindle that no longer turns the mechanism, a spring that has given up, a strike that was installed for a different backset—these are hardware swaps. Take the old latch to the store. “Close enough” backset is how you drill a second hole in a door you liked.
When the Wood Has Grown
Solid-wood doors and even some composite edges swell in humid months. A light rub at the latch edge or the bottom corner in August that disappears in January is not a reason to plane for winter. Wait for the wet season, mark the shiny spot where paint has burnished, and take off a little with a block plane or a sanding block. Prime and paint the raw edge the same day or that edge will drink moisture and swell again.
If the door hits the floor or a new rug, check the bottom gap. Shortening a hollow-core door is possible if you stay in the solid edge band. Cut too far and you open the cardboard cells. Measure twice. A door bottom that drags can also mean the whole slab dropped at the hinges. Fix the hang first so you do not create a winter undercut you will regret.
The Door That Will Not Stay Closed
Gravity wins when the hinge axis leans toward the opening. Sometimes a slight bend in a hinge pin adds just enough friction. Sometimes the better fix is to bring the jamb back toward plumb with longer screws and a shim. Forcing a closer or a magnet on an interior door that should latch is a workaround. It is acceptable in a crooked old house. It is not a substitute for a strike that actually receives the latch on a door you use twenty times a day.
Bathroom doors that will not stay shut fight the exhaust fan. A fan that is trying to pull air under a door that is standing open does a worse job of clearing steam. Getting that latch to click is a moisture control task as much as a privacy one. Bedroom doors that stand ajar change how supply air moves; not an energy crisis, but a comfort quirk in houses that already struggle to balance rooms.
Energy and the Quiet Side Effects
Interior doors are not weatherstripping projects. The energy story is indirect. A bathroom door that closes lets the fan work on the room instead of the hallway. A tight latch on a door to an unused room can keep a vent from dumping heat into a space you are not using. None of that replaces attic insulation. It is just the house behaving the way the mechanicals expect.
Trade-Offs
Longer hinge screws are fast and reversible. Planing is slower and permanent. New hardware looks clean and fails if you ignore alignment. Replacing a slab because you did not want to fuss with a strike plate is how hollow-core doors multiply in the garage.
Old houses will never be perfectly square. The aim is a latch that catches, a swing that does not saw the casing, and a gap that looks even enough that you stop noticing it.
Click, Then Forget It
When the door shuts with a modest push and stays there, you are done. The work was in the hinges, the strike, and maybe a whisper of wood off the edge. The slab was rarely the villain.