Large open-span structures like arenas, gymnasiums, and sports complexes are architectural feats that serve communities, athletes, and spectators alike. However, in snow-prone regions such as Ontario, these buildings face a formidable natural challenge each winter: heavy snow accumulation.
If left unaddressed, snow loads can result in severe structural stress, long-term damage, or even catastrophic roof collapse. Proper design, construction, and maintenance are essential to ensure safety, compliance, and building longevity.
Why Snow Loads Matter for Open-Span Buildings
Unlike traditional buildings with interior load-bearing walls, large-span structures rely on long, uninterrupted roof systems supported by trusses or steel frames. While this design offers clear interior space, it makes the roof particularly vulnerable to:
- Uneven snow distribution (especially from drifting and wind loading),
- Accumulated weight over large surface areas,
- Dynamic snow events (freeze-thaw cycles or rain-on-snow).
These factors can significantly exceed design load limits, particularly on flat or low-slope roofs.
Structural Engineering for Snow Load Resistance
To address this, building codes in Canada (such as the Ontario Building Code) mandate that commercial roofs be engineered to support specific snow loads based on regional climatic data.
Key design strategies include:
- Enhanced roof slope: A steeper pitch facilitates natural snow shedding.
- Load redistribution systems: Structural redundancies help spread snow weight across multiple support points.
- Roof truss optimization: Reinforced steel or laminated wood trusses increase load capacity without excessive material use.
- Drift load considerations: Roof step-downs, parapets, or adjacent taller structures can cause snow drift zones, requiring localized strengthening.
Professional structural engineers should use local climate data from Environment Canada and apply standards from the Canadian Standards Association (CSA S136 and S832) when modeling load scenarios.
Best Roofing Materials for Snow Resilience
Not all roofing systems perform equally under snow stress. For arenas and gymnasiums, materials must handle freeze-thaw cycles, resist corrosion, and allow for safe snow removal.
Top choices include:
- Standing seam metal roofs: Durable, snow-shedding, and compatible with snow guards and heating cables.
- EPDM and TPO membranes: Common for flat roofs, especially with structural enhancements.
- Modified bitumen: Strong, layered, and ideal for resisting punctures or water infiltration during snow melt.
Additionally, snow retention systems (like snow guards or fences) can prevent dangerous snow slides that damage equipment or injure bystanders.
Snow Load Maintenance & Monitoring
Even with good design, snow removal and monitoring protocols are vital:
- Install real-time load monitoring sensors to track roof stress levels.
- Train maintenance teams to safely perform snow removal without damaging roofing membranes.
- Schedule post-storm inspections to detect hidden leaks, stress fractures, or insulation issues.
Failing to monitor loads can result in costly insurance claims, roof deformation, or business disruption.
Insurance and Liability Considerations
Under Ontario law, property owners and managers are responsible for ensuring that snow accumulation does not endanger occupants or neighboring properties. Insurers often require proof of:
- Load capacity documentation,
- Maintenance logs,
- Snow removal contracts with licensed providers.
Neglecting these responsibilities can invalidate policies or lead to legal liabilities in the event of structural failure.
Conclusion
Heavy snow loads present a serious risk to large-span buildings like arenas and gymnasiums, but with proper design, durable roofing, and proactive maintenance, these facilities can operate safely throughout harsh winters.
Investing in snow-resilient engineering isn’t just a regulatory requirement—it’s an essential part of protecting people, property, and reputations.