An interior door that scrapes the threshold or refuses to close cleanly is the most common annoyance in older homes. The fix is almost always cheaper and faster than homeowners expect. A sagging door usually traces to one of three culprits: loose hinge screws, shifted framing from settling, or worn hinges themselves. Diagnose the cause correctly and you can return any door to factory operation in 20 to 60 minutes with about $15 in hardware. Get it wrong and you can chase the symptom for years without fixing the real problem.
Part of our Windows & Doors guide — explore the full guide →
- Diagnose Before You Fix
- The Long Screw Trick
- Shim Loose Hinges to Square the Door
- Mortise Worn Out Beyond Repair
- Replace the Hinges Entirely
- Address Frame Movement and Settling
- Planing the Door as a Last Resort
- When the Door Slab Itself Is Warped
- Common Mistakes That Make Things Worse
- Maintenance That Prevents Future Sag
Diagnose Before You Fix
Open the door halfway and lift the knob side gently. If the door has play and the hinge side flexes, you have loose screws or hinge mortise wear. Close the door and watch where it contacts the frame. Scraping the bottom strike side typically means the top hinge has pulled away. Scraping the top strike side means the bottom hinge has loosened.
Run a level along both edges of the door slab. A perfectly square door in a racked frame is a different problem than a warped door in a square frame. The first requires reframing or shimming the hinges. The second requires replacing the door slab or accepting the cosmetic issue.
The Long Screw Trick
The single most effective fix for a sagging door takes about 10 minutes. Remove one of the short 3/4-inch screws from the top hinge (on the jamb side) and replace it with a 3-inch GRK Cabinet Screw ($1 each, sold in 10-packs at Home Depot) or a Spax PowerLags 3-inch. The long screw bites into the wall framing behind the door jamb, pulling the entire hinge tight against solid wood instead of just the thin jamb material.
Predrill with a 1/8-inch bit to prevent splitting the existing jamb. Drive the screw flush with the hinge surface but stop before crushing the hinge plate. One long screw per hinge handles 90 percent of sagging door problems. Two long screws per hinge handles the rest.
Shim Loose Hinges to Square the Door
If long screws alone do not solve the problem, the door may need its hinges shimmed to change the swing angle. Cut a cardboard shim from a cereal box or playing card to fit behind the hinge that needs adjustment. Loosen the hinge screws, insert the shim, and retighten.
Shimming behind the top hinge moves the latch side of the door toward the strike. Shimming behind the bottom hinge moves it away. A 1/16-inch shim creates a noticeable change at the latch edge of a 30-inch wide door. For larger adjustments, stack two or three shims, but expect to repeat the process within years as the door settles into the new position.
Mortise Worn Out Beyond Repair
Older homes with original wood doors sometimes show hinge mortises so worn that screws spin in place. Repair starts by drilling out the worn screw hole, gluing in a hardwood plug (Bondo wood filler or Elmer’s Carpenter’s Wood Filler Max work too, $6 each), and re-drilling the pilot hole once the filler sets.
For severely worn mortises, the Stanley Wood Plug ($4 for a 25-pack) provides a clean dowel of solid wood. Drill out the existing hole to 3/8 inch, glue in the plug, trim flush, and chisel a new screw pilot. The result is structurally as strong as original work and lasts the life of the door.
Replace the Hinges Entirely
Hinges wear out. Cheap brass-plated steel hinges in 1980s and 1990s tract homes often develop play within 20 years. Replacement with quality hinges from Hager (4-inch standard residential at $4.50 each) or Stanley Black and Decker ($5 each) restores tight, quiet operation. Specify ball-bearing hinges for heavier solid-core doors at $8 to $12 each.
Match the hinge size and screw hole pattern to the existing mortise. Most residential interior doors use 3.5-inch hinges, but older homes occasionally have 4-inch or non-standard hinges that require slight mortise modification. Buying one extra hinge for the project gives you a template for any mortise rework.
Address Frame Movement and Settling
Houses move. Foundations settle, framing shifts seasonally, and door frames go out of square. If long screws and new hinges fail to solve a sagging door, check whether the frame itself has gone out of plumb. A 4-foot level held against the hinge-side jamb tells you immediately.
Out-of-plumb frames need shimming behind the jamb to bring the door back into operating geometry. Pry off the casing, loosen the existing finish nails, insert shims at the appropriate height, and re-nail. This is a 1 to 2 hour job for a competent DIYer and runs $200 to $400 for a contractor.
Planing the Door as a Last Resort
If the door physically does not fit the opening anymore, planing the slab edges can buy years of operation. A Stanley 12-205 block plane ($35) handles most jobs. Mark the contact area with pencil, remove the door from its hinges, support it on edge between sawhorses, and plane in light passes until the contact mark disappears.
For larger adjustments, an electric hand planer like the Wen 6530 ($65) cuts faster but requires more skill to avoid gouging. Remove only the absolute minimum. Repaint or refinish the cut edge to seal the exposed wood and match the rest of the door.
When the Door Slab Itself Is Warped
Wood doors warp from differential humidity exposure. A door that faces a heated interior on one side and a cold garage on the other often warps within years. Once warped beyond 1/4 inch, replacement is usually the right call.
Solid-core doors from Masonite, Jeld-Wen, and Builders Surplus run $80 to $200 for standard sizes. Pre-hung units with the door already installed in a new jamb cost $180 to $400 and save considerable installation time. Match the swing direction (left-handed or right-handed) before ordering.
Common Mistakes That Make Things Worse
Tightening loose hinge screws repeatedly strips them further. Once a screw spins, replace it with a longer screw that grabs new wood or repair the hole. Continuing to torque a stripped screw eventually destroys the mortise and forces a much bigger repair.
Adding a third hinge to a two-hinge door rarely fixes a sagging door problem and often makes the situation worse by introducing alignment conflicts. Most interior doors are designed for two hinges sized correctly. Heavy solid-core doors over 32 inches wide sometimes warrant a middle hinge from the factory.
Maintenance That Prevents Future Sag
Twice a year, check every interior door for play at the hinges. Tighten any loose screws before they strip. Lubricate hinge pins with a dab of 3-in-One Oil or Dupont Teflon Multi-Use Lubricant ($8) to prevent the squeaking that signals dry pins and accelerated wear.
Investing 20 minutes per year across an entire house prevents 90 percent of sagging door problems from ever developing. For doors that already sag, the long screw trick remains the highest-leverage fix in any homeowner’s toolkit. Try it first, and the rest of the repair often becomes unnecessary.
