Yes, re-hanging or adjusting a dropped door is generally a job a confident DIYer can tackle — no building consent is required for like-for-like door repairs, and no licensed trade is involved. That said, if the dropping is caused by structural movement or foundation issues, you'll want a professional assessment before you reach for the screwdriver.
Why Do Doors Drop?
Before you start work, it pays to understand what's caused the problem. The most common culprits are:
- Loose hinge screws – The most frequent cause. Screws work loose over time, especially in older timber frames.
- Worn or damaged hinges – The hinge knuckle wears, allowing the door to sag on its pivot point.
- Timber movement – NZ's variable humidity causes timber to swell, shrink, and twist seasonally. This is especially common in older villas and bungalows with native timber frames.
- Settling or subsidence – The house frame has moved, racking the door opening out of square.
- Incorrect installation – The door was never hung quite right to begin with.
Identifying the cause first will save you time and frustration.
What You'll Need
- Screwdrivers (flathead and Phillips)
- Cordless drill
- Hammer and chisel
- Timber toothpicks or matchsticks and PVA glue (for filling stripped screw holes)
- Replacement hinges (if needed — available at Bunnings or Mitre 10)
- Long 75 mm screws (sometimes called "structural screws" or structural screws)
- Pencil and combination square
- Hand plane or belt sander (if trimming is needed)
- Safety glasses
Step 1 – Check and Tighten the Hinges
Open the door and inspect all hinges — most interior doors have two, exterior doors often have three. Try wiggling the door; if there's play at the hinge, that's your problem.
Tighten every screw first. If screws spin without gripping, the holes are stripped. Remove the screw, pack the hole with a toothpick or matchstick dipped in PVA glue, let it dry for an hour, then re-drive the screw. This simple fix solves the majority of dropped doors.
For extra holding power on exterior doors or heavy solid-core doors, replace the standard short hinge screws with 75 mm screws that reach through the door jamb and into the structural framing behind it. This is a well-known trade trick that dramatically improves hinge strength.
Step 2 – Inspect the Hinges Themselves
If the hinges are visibly bent, corroded, or the knuckle is worn, replace them. Take the old hinge to the hardware store to match the size and style. Standard NZ interior door hinges are typically 75 mm (3 inch) butt hinges.
When fitting new hinges, check that the hinge recess (mortise) in the jamb and door edge is the right depth. A hinge sitting proud of the timber will cause the door to bind on the latch side; one set too deep will cause a gap. Use a sharp chisel to adjust the mortise depth as needed.
Step 3 – Check the Frame for Square
Use a combination square or spirit level to check whether the door frame is still plumb and square. If the frame has racked — common after earthquakes, subsidence, or significant timber movement — simply re-hanging the door won't give a lasting fix.
Minor racking can sometimes be compensated for by adjusting hinge depths (shimming one hinge slightly proud or deeper). Significant racking needs a joiner or builder to assess the frame.
Step 4 – Trim the Door If Needed
If the door has swollen or the frame has dropped slightly, you may need to trim the bottom of the door. Mark the cut line with a pencil, allowing a 3–5 mm clearance above the floor (more if carpet is fitted, or if you're meeting Healthy Homes ventilation gap requirements for rental properties — check Tenancy Services for current standards).
Use a hand plane for small amounts (1–2 mm) or a circular saw with a guide for larger cuts. Always seal any cut end grain on exterior doors with primer or paint to prevent moisture ingress — a key consideration in NZ's damp climates.
Step 5 – Re-Hang the Door
With hinges repaired or replaced and any trimming done, re-hang the door and check the reveal (the gap around the door) is even — typically 2–3 mm on the sides and top, 3–5 mm at the bottom. Test the door swings freely, latches cleanly, and doesn't scrape.
A Note on Building Consents
Like-for-like repair and maintenance of an existing door — including re-hanging, hinge replacement, and minor trimming — is exempt from building consent under Schedule 1 of the Building Act 2004. However, if you're replacing a door with a different size or type, or altering the frame structurally, check with your local council. You can find guidance at MBIE Building Performance.
When to Call a Professional
Call a qualified joiner or builder if:
- The door frame is visibly racked, twisted, or out of plumb by more than a few millimetres
- You suspect foundation movement or subsidence — this needs a structural assessment
- The door is a fire door (these have specific performance requirements and should be maintained by someone familiar with the relevant standards)
- You're not confident using a plane or chisel without damaging the door
- The problem keeps recurring despite your repairs
A skilled joiner can diagnose and fix a dropped door quickly. You can find qualified local joiners and builders on tradedirectory.co.nz.
