Canada Ramp Slopes (NBC 9.8)

The requirement

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.

That 1 in 10 covers a residential ramp only. The code sets steeper limits for other jobs. Keep them straight so you do not mix them up.

What you’re building	Max ramp slope
A house / residential ramp (inside or out)	1 in 10
Any other occupancy (shops, offices)	1 in 8
Industrial	1 in 6

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. You also always need a level landing at the top and bottom.

Any ramp steeper than 1 in 50 needs those top and bottom landings. The landing itself must be near level. Its slope can be no steeper than 1 in 50.

NBC 2020, Div B, 9.8.5 (Ramps)

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. It commonly runs around 1 in 12, with 1 in 20 preferred. 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?

Pick the slope. A house ramp can be 1 in 10 at the steepest. That means for every 1 up, you travel 10 along.
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.
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.
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

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, 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.)

Frequently asked questions

What's the steepest ramp allowed for a house in Canada?

1 in 10. Under the National Building Code, Part 9, a ramp serving a residential occupancy can be 1 in 10 at the steepest. That is 100 mm along for every 10 mm you climb. Same limit inside or outside. The 1 in 8 and 1 in 6 limits are for other and industrial occupancies.

Do I need a landing partway up a long ramp?

Yes, once the ramp climbs more than 1500 mm. A house ramp at 1 in 10 is steeper than 1 in 12, so the rise between landings is capped at 1500 mm. At 1 in 10 that is about 15 m of run. You also need a level landing at the top and bottom.

How wide does a house ramp have to be?

At least 860 mm for a ramp serving a single dwelling unit. Ramps generally must be at least 1100 mm wide. The code allows the narrower 860 mm for a ramp inside or serving one home.

Does every ramp need a landing at the ends?

A landing is required at the top and bottom of any ramp steeper than 1 in 50. The landing itself must be close to level. Its slope can be no steeper than 1 in 50.

Isn't the ramp limit 1 in 12?

That is the barrier-free rule in NBC Section 3.8, for a required accessible route. A normal single-family house usually does not need a barrier-free path, so Part 9's 1 in 10 governs. If your ramp is on a required barrier-free route, do not use 1 in 10. Check Section 3.8.