Can Cold-Formed (Light Gauge) Steel Be Used for Multiplex Buildings in Toronto?

As Toronto pushes for gentle density, multiplex housing, and faster construction methods, cold-formed steel (CFS)—also known as light gauge steel framing (LSF)—is getting more attention as an alternative to wood and concrete. A common question that comes up is:

Can cold-formed steel be used for a 4-story multiplex in Toronto?

The short answer is yes—but only when it is properly engineered and code-compliant. Here’s what designers, builders, and owners need to know. 

 What Is Cold-Formed (Light Gauge) Steel Framing?

Cold-formed steel framing consists of thin steel members (studs, tracks, joists) formed at room temperature. It’s widely used for interior partitions, but it can also serve as primary structural framing in residential and mid-rise buildings when designed correctly.

Key advantages include:

• High strength-to-weight ratio

• Non-combustible material

• Dimensional stability (no shrinkage or warping)

• Compatibility with prefabrication and panelized construction

• Resistance to mold, rot, and insects

Because of these benefits, CFS is increasingly used in multi-unit residential construction across Canada.

 Is Cold-Formed Steel Allowed by Code in Toronto?

Yes. Toronto follows the Ontario Building Code (OBC), which is based on the National Building Code of Canada (NBC). Both codes recognize cold-formed steel as a structural material.

Cold-formed steel design in Canada is governed primarily by:

·         CSA S136 – North American Specification for the Design of Cold-Formed Steel Structural Members

There is no code prohibition against using cold-formed steel for a 4-story residential building. However, unlike low-rise wood construction, cold-formed steel is not a prescriptive system in this context.

ü All structural cold-formed steel buildings of this scale must be engineered.

 Can Cold-Formed Steel Support a 4-Story Multiplex?

Yes—4 stories is well within the proven capabilities of cold-formed steel, provided the system is properly designed.

In practice:

·         Load-bearing walls, floor joists, and roof framing can all be built using heavier-gauge CFS members

·         Lateral loads (wind and seismic) are handled using engineered shear walls, strap bracing, or steel moment frames

·         Many projects use hybrid systems, such as:

CFS walls with concrete or steel deck floors

Hot-rolled steel elements at podiums or transfer levels

Cold-formed steel has been successfully used in mid-rise residential buildings (4–6 stories and higher) in Canada and internationally.

 Fire and Life-Safety Considerations

Because cold-formed steel is non-combustible, it performs well from a fire-safety perspective—but fire resistance ratings still matter.

For a 4-story multiplex, the design must demonstrate:

• Required fire-resistance ratings for floors, walls, and shafts

• Proper fire separations between dwelling units

• Use of tested and listed assemblies (typically gypsum-board protected steel framing)

All of this must be clearly shown on permit drawings and backed by engineering and code analysis.

 Why Engineering Is Mandatory

Unlike small wood-frame buildings, you cannot rely on prescriptive tables for a 4-story cold-formed steel multiplex.

A licensed Ontario structural engineer must:

• Design all gravity and lateral systems

• Specify steel thicknesses, connections, and bracing

• Verify deflection, vibration, and serviceability limits

• Coordinate with architectural, fire, and acoustic requirements

• Seal drawings submitted for permit

Without stamped structural drawings, the City of Toronto will not issue a building permit.

 Practical Considerations for Builders and Developers

Cold-formed steel can be an excellent option, but it’s not a drop-in replacement for wood framing.

Things to plan for:

• Early coordination between architect, engineer, and steel fabricator

• Slightly higher upfront engineering costs (often offset by speed and precision)

• Use of prefabricated wall and floor panels for efficiency

• Careful detailing of thermal breaks and acoustics

When well-coordinated, CFS projects can build faster, straighter, and with less waste than conventional framing.

 Final Verdict

Yes—cold-formed (light gauge) steel framing is absolutely feasible for a 4-story multiplex in Toronto.

However:

• It must be fully engineered

• It must comply with the Ontario Building Code

• Fire, structural, and lateral systems must be clearly demonstrated

• Approval depends on design quality, not material choice

For the right project team, cold-formed steel can be a smart, modern solution for Toronto’s growing multiplex housing needs.