How to fix a sagging door

🪚 Trade Guide: How to Fix a Sagging Door

What causes a door to sag and how is it fixed?

A sagging door is typically caused by hinge loosening, frame movement, worn fixings, settlement, or leaf distortion, and it commonly presents as hinge-side drop, latch misalignment, or rubbing on the jamb or floor. The correct repair method depends on identifying whether the fault sits with the hinges, jamb, frame, fixings, or the door leaf itself, and the objective is always to restore consistent margins and reliable latch engagement without creating new binding points.

This guide covers a professional fault-finding and rectification process suitable for internal and external hinged doors in residential and light commercial settings, with methods aligned to good trade practice and relevant framing considerations under AS 1684 Residential Timber-Framed Construction where frame movement or settlement is involved.

What skill level is required to fix a sagging door?

Intermediate — Estimated time: 1.5 to 4 hours depending on fault severity and whether rehanging, packing, or planing is required

What tools are essential for fixing a sagging door?

What materials are needed to fix a sagging door?

🪵 Materials

Safety Requirements

⚠️ Safety

Step-by-Step Guide

Step 1: Inspect the fault and diagnose the sag pattern

1️⃣ Identify the contact points

Open and close the door slowly and observe where it binds. Typical signs include the top latch-side corner rubbing the head jamb, the latch not aligning with the strike, or the bottom edge dragging on finished flooring.

Check the margins around the leaf. A well-hung door should present an even reveal, typically around 2 mm to 3 mm on the jambs and head, subject to door type and hardware specification. If the top hinge-side margin is tight and the latch-side top margin is large, the leaf has generally dropped off the hinge side.

💡 Mark rubbing points with masking tape or pencil before making any adjustment. This avoids chasing multiple faults once the door position changes.

Step 2: Check hinges, screws and jamb integrity

2️⃣ Confirm whether the problem is fixings or joinery movement

Inspect all hinges for loose screws, enlarged screw holes, worn knuckles, bent leaves, or hinge gains cut too deep. Start with the top hinge, as this is most commonly responsible for sagging.

Check whether screws are biting into solid jamb timber and framing, or only into the jamb lining. If the top hinge screws are short, replace one or two with 8G x 50 mm or 8G x 65 mm countersunk screws to pull the jamb and hinge leaf back into the stud/frame behind.

Also inspect the jamb for movement, split timber, or pulled fixings. If the jamb itself has shifted, simply adjusting the leaf will not provide a durable repair.

Step 3: Tighten and reset the top hinge

3️⃣ Pull the door back into alignment

With the door supported on wedges, tighten all hinge screws firmly by hand or with a clutch-controlled driver. Avoid overdriving, which can strip old jamb material.

If the top hinge is loose, remove one screw at a time and replace with a longer fixing into solid framing. In many cases, installing one or two 8G x 65 mm screws through the top hinge jamb leaf will lift the latch side of the door back into alignment.

Close the door and reassess margins after each screw replacement rather than driving all fixings at once. Small hinge movements produce a noticeable effect at the latch side.

💡 A single long screw in the top hinge jamb leaf, positioned through the middle or upper screw hole, often provides the cleanest correction without invasive work.

Step 4: Repair stripped screw holes properly

4️⃣ Rebuild fixing capacity in the jamb or leaf

If screws spin freely, remove the affected screws and repair the holes. For minor wear, glue in timber matchsticks or slivers of hardwood with PVA and trim flush once set. For a more durable trade repair, drill out and glue in a hardwood dowel, then redrill pilot holes.

Do not rely on oversized screws alone if the surrounding timber is crushed or split. The repair needs proper bite so the hinge can carry long-term load.

If the door leaf stile is stripped, apply the same method in the leaf side, taking care not to break out through veneer or edge lipping on flush panel doors.

Step 5: Pack or recut hinge gains where required

5️⃣ Correct hinge geometry

If the hinge gain is cut too deep, the leaf may sit too far into the jamb and sag visually even when the screws are sound. Remove the hinge and install a card packer or thin plastic shim behind the hinge leaf to bring the door back into plane.

If a hinge gain is poorly set out, bruised, or oversized, square it up with a sharp chisel and repack neatly. If the hinge leaf is proud because the gain is too shallow, deepen it carefully with a chisel to the exact hinge thickness.

The aim is for the hinge leaf to sit flush with the timber face, with no twist in the hinge when screws are tightened.

💡 Keep packers full-size to the hinge leaf where possible. Small offcuts behind only one area of the hinge can distort the leaf and create bind.

Step 6: Adjust latch-side alignment and strike position

6️⃣ Restore latch engagement after hinge correction

Once the door is hanging correctly, check the latch against the strike plate. If the latch is still low or misaligned, mark the latch tongue position with pencil or lipstick and transfer the mark to the strike area.

Minor strike misalignment can be corrected by removing the strike plate and extending the mortice slightly with a chisel or file, then resetting the plate. If the strike plate position changes significantly, plug old screw holes and refix properly.

Do not move the strike plate before resolving hinge sag. Otherwise, the latch may engage temporarily while the underlying door drop remains.

Step 7: Plane the door only if adjustment alone will not fix the problem

7️⃣ Remove material as a last correction step

If the frame has moved or the door leaf has swollen and margins cannot be corrected through hinge work, remove the door and plane only the affected edge. Mark the cut line from actual contact points and maintain a straight, consistent arris.

Take light passes with a sharp block plane or electric planer and continuously check for fit. On painted doors, seal the freshly exposed timber immediately after trimming. On external doors, ensure the bottom clearance and edge sealing remain suitable for moisture exposure.

Typical trimming should be minimal. Excessive removal from one edge can throw off lockset backset appearance, weather sealing, and visual symmetry.

💡 For external doors, seal all planed edges, especially bottom rails, to reduce future moisture uptake and repeat sag complaints.

Step 8: Confirm frame condition and settlement if the problem persists

8️⃣ Check the opening, not just the leaf

If the door still binds after hinge correction and edge trimming, check the jamb for plumb, bow, and twist using a 1.8 m spirit level and straight edge. Measure diagonals across the opening where accessible.

Look for settlement cracks, movement in architraves, or flooring changes that suggest the opening has gone out of square. If the jamb is out significantly, the repair may require partial jamb refixing, packer adjustment, or reframing support tied back to surrounding wall framing in line with AS 1684 principles.

Where the fault is caused by building movement rather than hinge wear, advise the client accordingly and document the limitation of a maintenance-only adjustment.

Step 9: Reassemble, test and finish

9️⃣ Carry out final operation checks

Rehang the door if removed, retighten all fixings, lubricate hinges and latch, and cycle the door repeatedly through full opening and closing. Confirm:

Touch up any planed or repaired surfaces with matching finish. Clean off pencil marks, remove tape, and provide the client with a note if the opening shows signs of ongoing structural movement.

Common Mistakes to Avoid

Pro Tips

Recommended Tools

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