A door that drags or sticks at the bottom is a common frustration in NZ homes, especially after a wet winter when timber swells with moisture. The good news is that in most cases you can trim the bottom of a door while it's still hanging — saving yourself the hassle of lifting it off the hinges entirely.
Why Doors Stick at the Bottom
Before you start planing, it pays to understand why the door is sticking. Common causes include:
- Seasonal timber swelling — very common in NZ's humid climates, particularly in older homes with solid timber doors
- New flooring or carpet installed after the door was hung
- House settlement causing the door frame to shift slightly
- Paint build-up over many years reducing the clearance gap
If the door has only recently started sticking and the weather has been wet, wait for a dry spell first — it may free up on its own. If the problem persists, it's time to plane.
Tools You'll Need
- Sharp hand plane (a No. 4 or No. 5 bench plane works well) or a power hand planer
- Pencil or chalk
- Coarse sandpaper (80–120 grit) and a sanding block
- Primer and paint or timber sealer to finish
- A piece of cardboard or thin timber to protect the floor
A sharp blade is essential — a blunt plane will tear the timber grain rather than cut it cleanly. If you're using a hand plane, hone the blade before you start.
Step 1 — Mark Exactly Where It's Rubbing
Slide a piece of cardboard or thin card under the door and open and close it a few times. The card will show you where the door is making contact. Alternatively, rub a pencil or chalk along the floor where the door drags — it will transfer a mark onto the door bottom showing the high spots.
Step 2 — Protect the Floor
Lay a strip of cardboard or a thin offcut of timber along the floor directly under the door. This protects your flooring from the plane's sole and any shavings.
Step 3 — Plane With the Door in Place
With the door open and held steady (wedge it open with a doorstop or have a helper hold it), work the plane along the bottom edge. Key tips:
- Plane with the grain where possible — on most doors this means working from each end towards the centre to avoid splitting the corners
- Take light, even passes rather than trying to remove a lot of material at once
- Check your progress frequently by closing the door and testing the clearance
- Aim for a 2–3 mm gap between the door bottom and the floor — enough for smooth operation without letting draughts in
Using a Power Planer
A power hand planer removes material quickly, so be especially cautious. Set the depth of cut to no more than 0.5–1 mm per pass. Keep the tool moving steadily and avoid dwelling in one spot. Always wear eye protection and hearing protection when using power tools.
Step 4 — Check the Gap and Fine-Tune
Close the door and check the gap along the full width. Use sandpaper on a block to smooth any rough spots or slight ridges left by the plane. The bottom edge should be flat and even.
Step 5 — Seal and Paint the Edge
This step is often skipped but it's important — bare timber absorbs moisture, which is likely what caused the swelling in the first place. Apply a coat of primer followed by your topcoat paint, or use a timber sealer if the door is stained. This helps prevent the problem recurring. Resene and Dulux both offer suitable primers and exterior/interior paints for timber doors.
Tips for Different Door Types
| Door Type | Notes |
|---|---|
| Solid timber | Planes easily; grain direction matters |
| Hollow-core (MDF/hardboard skin) | Only a small amount can be removed before you hit the internal frame — typically no more than 10–15 mm total |
| Aluminium or composite | Planing is not suitable; consult a joiner |
| Fire doors | Do not modify without checking manufacturer specs and NZ Building Code compliance |
For hollow-core doors, check whether there is a solid timber rail at the bottom before planing — most have one, but it's worth confirming by tapping along the bottom edge (it will sound solid rather than hollow).
Preventing the Problem in Future
- Keep the bottom edge of the door sealed and painted at all times
- Ensure good ventilation in rooms prone to humidity — see guidance from Energywise on managing moisture in NZ homes
- If you're a landlord, note that Tenancy Services Healthy Homes standards require adequate ventilation and draught stopping, which affects door and floor gap requirements
When to Call a Professional
If the door is sticking badly, the frame looks twisted or out of square, or the problem keeps returning, there may be a structural issue with the building — such as foundation movement or framing settlement. In that case, it's worth having a qualified joiner or Licensed Building Practitioner (LBP) assess the situation. Modifying fire-rated doors or doors in certain commercial or multi-unit settings may also require professional sign-off under the NZ Building Code.
You can find experienced local joiners and carpenters on tradedirectory.co.nz who can assess and fix door problems quickly and correctly.
