Test #1: Does the latch retract when you turn the handle?
Hold the door open and turn the handle. If the latch bolt (the spring-loaded angled piece) doesn't fully pull back into the door, the lockset mechanism is failing. This is mechanical wear, sometimes a broken spring inside. The fix is a new lockset — $50 for the hardware, $95–$200 installed.
Test #2: Is the strike plate misaligned?
If the latch retracts fine but the door still won't catch, look at the strike plate (the metal plate on the door frame where the latch lands). Often the door has settled or the frame has shifted, and the latch is hitting above, below, or sideways of the strike hole. Look for a shiny scrape mark on the plate — that's where the latch is hitting.
Test #3: Is the door dragging?
If the latch never reaches the strike plate, the door itself is sagging. Top-front corner rubbing the jamb is the most common — it means the upper hinge screws are loose or stripped. Two minutes with a screwdriver and a couple of 3" wood screws into the framing usually solves it.
Quick fixes you can do yourself
- Tighten the hinge screws. Replace the short factory screws with 3" screws that bite into the framing — this corrects most sag.
- File the strike plate hole. If the latch is hitting just below the strike opening, file the opening 1/16"–1/8" wider with a metal file.
- Bend the strike tab. Some strike plates have a curved tab that can be bent to catch a slightly off-center latch.
When to call a pro
If hinge screws don't fix the sag, the jamb itself may be out of plumb — that's a door re-hang ($120–$250). If the latch mechanism is broken, a new lockset ($95–$200). If the door has swollen from moisture, planing the bottom edge ($85–$150). We diagnose for free.
