How to Repair a Sagging Interior Door That Drags on the Floor

A door that drags on the floor is one of the most common household annoyances, and the good news is that most causes are easy to fix yourself with basic tools. The culprit is almost always loose or worn hinges, but it can also be a warped door, a settling frame, or swelling caused by moisture — all common issues in New Zealand's varied climate.

Diagnose the Problem First

Before reaching for a plane or a screwdriver, take a few minutes to understand what's actually happening. Open and close the door slowly and watch where it binds or drags.

• Dragging at the bottom corner opposite the hinges — almost always a hinge problem.
• Dragging along the full bottom edge — the door may have swollen from moisture, or the floor has risen (common after new flooring is laid).
• Dragging at the top latch side — the frame may have racked or the house may have settled.
• Visible gap at the top hinge side — a strong sign the hinges are loose or the hinge mortises have worn.

Check each hinge by gripping the door near the hinge and gently pushing up and down. Any movement means the hinge needs attention.

Fix 1: Tighten or Replace Hinge Screws

This is the most common fix and takes about 15 minutes.

1. Open the door and prop it in place with a wedge or a folded piece of cardboard under the latch side.
2. Check every screw in every hinge — both the door leaf and the frame leaf.
3. Tighten any loose screws with a screwdriver (not a drill on full torque, which can strip the hole further).
4. If a screw spins freely and won't grip, the timber hole is stripped.

Fixing Stripped Screw Holes

This is the number-one cause of sagging doors. You have a couple of reliable options:

• Longer screws: Replace the standard short hinge screws (often only 25–30 mm) with 65–75 mm screws that reach through the door jamb and into the structural framing behind it. This is often a permanent fix on its own.
• Timber toothpicks or matchsticks: Pack the stripped hole with wooden toothpicks and a dab of PVA glue, let it dry, then re-drive the original screw. Works well for minor stripping.
• Timber dowel plug: For badly stripped holes, drill out to 8 mm or 10 mm, glue in a timber dowel, let it cure fully, then re-drill a pilot hole and refit the screw.

Fix 2: Repack or Replace the Hinges

If the hinges themselves are bent, corroded, or the hinge mortise (the recess cut into the timber) is too deep, the door will sit low on the hinge side.

• Shimming a hinge: Cut a shim from thin cardboard or buy purpose-made hinge shims. Remove the hinge, place the shim in the mortise, and refit the hinge. This lifts the door slightly and can eliminate a drag.
• Replacing hinges: If a hinge is visibly bent or the knuckle is worn, replace it like-for-like. Standard NZ interior door hinges are typically 89 mm (3½ inch) butt hinges. Take the old hinge to Bunnings or Mitre 10 to match it.

Fix 3: Plane or Sand the Door Edge

If the hinges are all solid and the door still drags, you may need to remove a small amount of material from the door edge.

1. Mark the drag zone with a pencil or chalk while the door is closed.
2. Remove the door by tapping out the hinge pins (tap upward from below with a screwdriver and hammer).
3. Use a hand plane, belt sander, or orbital sander to remove material gradually — take off no more than 1–2 mm at a time.
4. Rehang and test before removing more.
5. Seal any bare timber edges with paint or primer immediately. Unsealed door edges are a leading cause of moisture swelling — particularly important in NZ bathrooms and laundries where humidity is high.

Fix 4: Address Moisture and Swelling

New Zealand's humid summers and wet winters mean timber doors often swell seasonally. If the door only drags in winter or after rain, moisture is likely the cause.

• Ensure the room is adequately ventilated. The Healthy Homes Standards require rental properties to have adequate ventilation, but good airflow benefits any home.
• Seal all six faces of the door (including top and bottom edges) with paint to reduce moisture uptake.
• A dehumidifier can help in persistently damp rooms.
• Check for leaks around windows or the roof that may be introducing moisture into the wall framing — if the frame itself is wet and swollen, that's a bigger issue to investigate.

Fix 5: Adjust for a Racked or Settled Frame

If your house has settled — common in older NZ homes on timber piles — the door frame itself may have moved out of square. You can confirm this with a spirit level on the hinge jamb.

Minor racking can sometimes be corrected by adjusting hinge positions. Significant frame movement, however, may indicate foundation or structural issues that go beyond a simple door repair. In that case, get a professional assessment.

When to Call a Professional

Most sagging door repairs are well within DIY reach, but call a qualified tradesperson if:

• Multiple doors and windows are sticking throughout the house — this can signal foundation movement or structural issues that need assessment by a Licensed Building Practitioner (LBP).
• The door frame is visibly cracked, twisted, or rotted and needs replacement — frame work that is part of the structural envelope may require a building consent; always check with your local council first.
• You're unsure whether the settling is ongoing or has stabilised.
• The door is a fire door (common between a garage and living space) — fire doors must be correctly fitted and self-closing to comply with the NZ Building Code; don't modify them without professional advice.

You can find experienced local handymen and carpenters on tradedirectory.co.nz who can sort a sagging door quickly and correctly.

Sources & Further Reading

• MBIE Building Performance — NZ Building Code
• Licensed Building Practitioners (LBP)
• BRANZ — Building Research
• Bunnings NZ — Tools & Hardware
• Mitre 10 NZ — Hardware & Hinges
• Tenancy Services — Healthy Homes Standards