Spiral Staircases and the Ontario Building Code: What You Need to Know

Spiral staircases are visually striking and take up minimal floor space — which is exactly why many Ontario homeowners consider them when planning a custom staircase. But the Ontario Building Code (OBC) has specific restrictions on where spiral staircases can be used as a primary means of access between floors, and these restrictions eliminate them as an option for most residential applications. At C.O.R.S Staircases in Barrie, we get questions about spiral staircases regularly — here’s an honest overview of what the OBC says and what your alternatives are.

What Is a Spiral Staircase?

A spiral staircase features tapered treads arranged in a helical pattern around a central pole or column. Each tread is wider at the outer edge than at the inner edge (adjacent to the column). The compact footprint — typically 1,200–1,800mm diameter — is the primary appeal. Spiral staircases are manufactured and custom-built in a range of materials including steel, wood, and a combination of both.

Can Spiral Staircases Be Used in Ontario Homes?

The Ontario Building Code permits spiral staircases in some, but not all, residential applications:

• Permitted as secondary/ancillary access: Spiral staircases are OBC-compliant when serving a secondary or supplementary access route — for example, access to a loft, deck, or secondary room where another code-compliant staircase also provides access to the same level. They can also be used in single-storey additions, hobby rooms, or loft spaces served exclusively by the spiral where the space is not a required sleeping area
• NOT permitted as the sole means of egress between main floors: A spiral staircase cannot be the only staircase connecting the main living floors of a residential building. OBC Section 9.8 effectively excludes spiral staircases from serving as the primary exit stair because they cannot meet minimum tread depth and riser height requirements across the full width of the tread
• The key OBC challenge: OBC minimum tread run requirements of 210mm cannot be met at the narrow inner edge of a spiral tread — only at a specific measurement point (typically 300mm from the outer handrail). This means spiral staircases have reduced usable tread depth and a higher risk of misstep, which is why the code limits their primary use

Why Spiral Staircases Are Often Not the Best Choice

Beyond the OBC restrictions, there are practical reasons why spiral staircases rarely deliver what homeowners envision:

• Moving furniture: Nothing can be carried up or down a spiral staircase except the person using it. Large furniture, appliances, and even mattresses are impossible to move between floors
• Child safety: The triangular taper of spiral treads creates challenges for small children and elderly users. The OBC restrictions reflect real safety concerns
• Long-term habitability: What seems visually exciting as a concept becomes daily frustration when living with a spiral staircase as the primary route between floors

Better Alternatives to Spiral Staircases in Ontario

If the appeal of a spiral staircase is its compact footprint and visual interest, consider these OBC-compliant alternatives that deliver more:

• Floating mono-stringer staircase: Takes the same floor plan area as a conventional staircase but is visually open and architecturally dramatic. Fully OBC-compliant for primary egress. Starts from $14,000
• L-shaped floating staircase: Changes direction to fit challenging floor plans while remaining OBC-compliant and maintaining the floating aesthetic
• Glass panel railing with compact design: A well-designed compact traditional staircase with frameless glass railings can feel surprisingly open while meeting all OBC requirements

Discuss Your Staircase Options with C.O.R.S

C.O.R.S Staircases builds OBC-compliant custom floating and traditional staircases throughout Barrie, Simcoe County, and the GTA. If you’re considering a spiral staircase and want an honest assessment of your options, call (705) 623-0371 — we’ll help you find the solution that works for your space and meets Ontario building code requirements.

Spiral Staircase Ontario: Related Resources

• Ontario Building Code staircase — complete OBC guide for all staircase types in residential buildings
• Types of staircases Ontario guide — spiral alternatives: floating mono-stringer, curved, and space-saving designs
• Floating staircase Ontario — the most common OBC-compliant alternative to spiral staircases for Ontario homes
• Floating vs. traditional staircase Ontario — design options for small footprints: L-shaped and floating stringer systems
• Staircase permit Ontario — permit requirements for custom staircase designs including compact systems

Explore OBC-compliant alternatives to spiral staircases: 705-999-0000 | corsstairs.ca/contact