The requirement
New Zealand does not set one ramp slope for a house and another for a shop. The rule book — D1/AS1, the Acceptable Solution for Clause D1 Access Routes — sorts ramps by the job the ramp does. Pick the type that matches your ramp, then read the slope off the table.
| Ramp type | Where it’s used | Max slope |
|---|---|---|
| Accessible ramp | step-free access routes | 1:12 |
| Common ramp, can get wet | outside, or anywhere it can be rained on | 1:10 |
| Common ramp, stays dry | indoors, kept dry | 1:8 |
| Service ramp | plant / service access only | 1:3 (footholds needed if steeper than 1:8) |
There is no “house ramp” number. D1/AS1’s table has no private, residential or household category — the types are keyed to accessible, common and service use. A ramp into a home fits none of them cleanly. So do not quote a single “NZ residential ramp gradient”: there isn’t one. In practice, if you want a step-free entry, build to the accessible 1:12. If it’s a plain dry ramp, the steepest walkable figure is 1:8. If it can get wet, don’t go past 1:10.
Landings
The flat bit at each end and along a ramp is the landing. D1/AS1 wants:
- a level landing at the top and bottom of every ramp;
- intermediate landings along the run for any ramp steeper than 1 in 33, spaced at the vertical intervals in Table 5.
How much a ramp can climb before it needs a landing depends on the type:
- Accessible ramp: rise up to 750 mm between landings; each landing 1200 mm long.
- Other ramps: rise up to 1500 mm between landings; the landing is as long as the ramp is wide, up to 900 mm.
Work it out on site
You’re building a step-free entry ramp into a home, so you’re aiming for the accessible 1:12. The door sits 450 mm above the path. How long is the ramp?
- Pick the type and slope. Step-free entry → accessible ramp → 1:12 at the steepest. 1:12 means 1 unit up for every 12 along.
- Do the sum. 450 mm up × 12 = 5400 mm, so 5.4 m of ramp run. (That 5.4 m is just the maths of this example, not a code figure.)
- Check the rise between landings. An accessible ramp can rise up to 750 mm between landings. Your 450 mm is under that, so one run is fine — no mid-ramp landing needed.
- Add the landings. A level landing 1200 mm long goes at the top and the bottom.
So: about 5.4 m of ramp at 1:12, with a 1200 mm landing at each end. The slope calculator does this rise-over-run sum for you.
Do it in 5 seconds
Related
- Part of the NZ Building Code rules for chippies — the hub, with the D1/AS1 access-route articles.
- Building the stairs that ramp might replace? See NZ stair & barrier rules.
Sources
- NZ Building Code Clause D1 Access Routes — Acceptable Solution D1/AS1 (2nd edition, Amendment 6) — ramp slopes by type at Table 3 (para 3.1.1) and landings at Table 5 (para 3.3.1): accessible 1:12, common wet 1:10, common dry 1:8, service 1:3; level landings top and bottom of every ramp; intermediate landings when steeper than 1 in 33; 750 mm rise / 1200 mm landing for accessible ramps, 1500 mm rise / up-to-900 mm landing for others. Read it at building.govt.nz. (D1/AS1 is one Acceptable Solution — a voluntary deemed-to-comply route to the mandatory Clause D1. You can instead use Verification Method D1/VM1 or an Alternative Solution. The 2nd edition, Amendment 6 has been current nationwide since 1 January 2017; confirm it is still the current amendment before you build.)
- Slip resistance is set by a separate standard — check AS/NZS 4586 and D1/AS1 Table 2 for the ramp surface, not the gradient rules above.
Related building rules
More New Zealand rules