When does a home ramp in Ottawa need a guard?

The Ontario Building Code requires a guard on a ramp or landing when the drop beside it is more than 600 mm. That is the trigger: not the slope, not the length, but how far someone could fall off the edge.

What the height rule means in practice

If the ground beside your ramp or landing drops away by more than 600 mm, a guard is required. The height the guard must reach depends on how high the walking surface is above the ground. Where the ramp or landing surface is not more than 1 800 mm above the ground, an exterior guard serving one dwelling unit must be at least 900 mm high. If the surface is more than 1 800 mm above the ground, the guard must be at least 1 070 mm high. Those are minimums under Part 9 of the Code, which is the section that governs houses.

A few other Code points that connect to this:

• Landings are required at the top and bottom of any ramp steeper than 1 in 50, and wherever a door opens onto the ramp. The guard rule applies to those landings as well, not only the ramp run itself.
• The ramp and landing surface must be wear-resistant, slip-resistant, smooth, even and free from open defects.
• Handrails are a separate question from guards. A ramp serving a single dwelling unit that rises not more than 400 mm does not require a handrail at all. Where a handrail is required, it must be between 865 mm and 1 070 mm high.

Guards and handrails are different things. A guard prevents a fall off the edge of a structure. A handrail gives something to hold while walking up or down. Your ramp may need one, both, or neither, depending on its rise and how the ground sits beside it.

The right first call is to the City's Building Code Services, because they can tell you whether your specific ramp needs a permit and how the guard rule applies to the drop and layout at your property. That answer shapes what the contractor needs to build.