Clear opening (door)
Clear opening is the unobstructed width through a fully-opened door, face-of-door to face-of-frame-stop. NCC H8 spec'd in clear opening, not door leaf size.
Ask Chalkline about this →Clear opening is the unobstructed width through a fully-opened door, measured between the face of the open door and the face of the frame stop on the opposite side. The NCC and AS 1428.1 specify accessibility requirements in clear opening terms, NOT door leaf size. A standard 820 mm door leaf with a typical frame and hardware can deliver less than 820 mm clear, failing the requirement. Builders must specify clear opening on the door schedule, not just leaf width.
The measurement (worked example):
For a 820 mm door leaf in a standard residential frame:
| Component | Width |
|---|---|
| Door leaf | 820 mm |
| Door thickness (when open at 90°) | 35 mm |
| Stop on opposite jamb | 15 mm |
| Clear opening | 820 - 35 - 15 = 770 mm |
Some standard residential 820 mm doors only deliver 755-775 mm clear. That fails the NCC H8 820 mm minimum.
Solutions to deliver 820 mm clear opening on an 820 mm leaf:
| Solution | How |
|---|---|
| Slim-line frame | Reduce frame stop from 15 mm to 5 mm (= ~10 mm gain) |
| Offset hinges (or “clear opening hinges”) | Swing the door clear of the jamb (= ~25-35 mm gain) |
| Wider door leaf (870 mm) | Use a 870 mm leaf to compensate for the loss (= reliable gain) |
| Cavity slider | Slides into wall cavity; no door-in-the-way loss (= 870-910 mm clear) |
| Bi-fold or pocket door | Folds out of the doorway |
The most reliable solutions are a wider door leaf (870 mm or 920 mm) or a cavity slider. Offset hinges work but add hardware cost.
Where the 820 mm clear opening applies (NCC H8 Silver):
- Main entrance to the dwelling (Silver).
- Path of travel to at least one bedroom and one bathroom on the entry level.
- Sanitary compartment doorway.
- Bathroom doorway containing the accessible shower.
For higher accessibility levels (AS 1428.1 strict compliance), the requirement steps up to 850 mm or 870 mm clear opening.
Common builder issues:
- Spec’ing 820 mm door without confirming clear opening: standard 820 mm + standard frame = 765-775 mm clear, failing H8.
- Hardware blocking the clear opening: D-handle protrusion can effectively narrow the clear opening 10-20 mm; lever handles and pull rings are less obstructive.
- Door schedule doesn’t list clear opening: drawings show door leaf size; builder assumes the leaf size is what the certifier measures; certifier measures clear opening and fails.
- Confusing rough opening with clear opening: rough opening (the framed hole in the wall) is yet a different dimension (rough opening > frame opening > door leaf > clear opening).
For builders:
- Spec clear opening on every Livable-Housing affected doorway in the door schedule. Don’t just write 820 mm leaf.
- Default to 870 mm leaf on H8 doorways to give margin.
- Spec cavity sliders or pocket doors for sanitary compartments where wall thickness allows; they deliver clear opening reliably and save manoeuvring space.
- Confirm hardware (handles, latches) doesn’t protrude into the clear opening width.
- Measure at handover: walk every H8 doorway with a tape, measure clear opening, fix any failures before PCI.
Also known as: effective clear opening, doorway clear width, clear door width.
Category: NCC / accessibility / doors.
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Last updated: 2026-05-15. Verified: 2026-05-15.