Canada Ramp Slopes (NBC 9.8)

The requirement

This is the NBC 2020 model-code baseline. Check the edition and changes in force in your province or territory before using it.

The steepest a house ramp can be is 1 in 10. That is set by the National Building Code (NBC), Part 9, the housing and small-buildings part. For every 10 mm you climb, you travel 100 mm along. The limit is the same whether the ramp is inside the house or outside it.

Article 9.8.5.4 applies the 1 in 10 cap to exterior ramps too. The steeper occupancy limits below concern interior ramps.

Landings and the 1500 mm rise rule

A house ramp at the 1 in 10 maximum is steeper than 1 in 12. So a second rule kicks in. The ramp can only climb 1500 mm before you break it with a level landing.

On a long ramp, that means a landing at least every 1500 mm of rise. At 1 in 10, that is roughly 15 m of run before you stop and land. Top and bottom landings are normally required too.

Any ramp steeper than 1 in 50 needs those top and bottom landings. Article 9.8.6.2(4) permits a bottom-landing exception for some clear exterior approaches. The landing itself must be near level, with slope no steeper than 1 in 50.

Width

A ramp serving a single dwelling must be at least 860 mm wide. Ramps in general have to be 1100 mm. The code lets you drop to 860 mm for a ramp that serves one home.

The one thing to check first

Part 9’s 1 in 10 is for an ordinary house ramp. If your ramp is on a barrier-free (accessible) path of travel, Part 9 hands off to Section 3.8. That section is much gentler. Use the exact limits and landing rules in Article 3.8.3.5. A normal single-family house usually does not have to provide a barrier-free path, so 1 in 10 governs. If an accessible route is required on your job, do not use 1 in 10. Check Section 3.8 first.

Work it out on site

You are building an exterior ramp to a side door. The door sits 600 mm above the finished ground. How long does the ramp need to be at 1 in 10?

1. Pick the slope. A house ramp can be 1 in 10 at the steepest. That means for every 1 up, you travel 10 along.
2. Do the sum. 600 mm up × 10 = 6000 mm, so 6 m of ramp run. This 6 m is just the maths of the example, not a code figure.
3. Check the rise limit. You can climb up to 1500 mm before you need a landing. A 600 mm rise is well under that. One run works, with no mid-ramp landing needed.
4. Add the landings. A level landing goes at the top and the bottom.

So: about 6 m of ramp at 1 in 10, with a level landing at each end. The slope calculator does this rise-over-run sum for you.

Do it in 5 seconds

Related

• Part of the Canada building codes hub — the NBC baseline and the province-by-province adoption tracker.
• Building the stairs that ramp might replace? See NBC stair & guard rules.

Sources

• NBC 2020 official second printing, Volume 2 §§9.8.5–9.8.6. Direct text checked 6 September 2026; includes 31 March 2025 errata.

• NBC 2020, Division B, Part 9, Subsection 9.8.5 (Ramps) — the 1 in 10 residential ramp slope (Article 9.8.5.4), the 1500 mm maximum rise between landings (Article 9.8.5.5), and the 860 mm / 1100 mm widths (Article 9.8.5.2). Confirm at nrc.canada.ca / Codes Canada.

• NBC 2020, Division B, Article 9.8.6.2 and 9.8.6.3 — landings at the top and bottom of any ramp steeper than 1 in 50, and the landing’s own 1 in 50 slope limit. Confirm at Codes Canada.

• NBC 2020, Section 3.8 (Barrier-Free Design) — for a ramp on a required accessible path of travel, the gentler slope rules come from here, not Part 9. (The NBC is a model code with no legal force until a province or territory adopts it, and several publish their own editions with changes — the BC Building Code, Alberta Edition, Ontario Building Code and Québec Construction Code. Always confirm the edition and any amendments your province has made.)