Ontario's ground snow load (Ss) ranges from roughly 1.5 kPa along Lake Erie to 4.5+ kPa near James Bay. Every MegaDome building Building Depot installs is stamped to the site-specific OBC snow load, with rain-on-snow surcharge (Sr) included. Here is how that calculation actually works.
Where to Find Your Site's Snow Load
OBC Supplementary Standard SB-1 publishes Ss and Sr values by Ontario municipality. London is 1.6/0.4 kPa. Toronto is 1.8/0.4. Ottawa is 2.4/0.4. Sudbury is 3.0/0.2. Thunder Bay is 2.0/0.2. Timmins is 3.5/0.2. We pull the values from SB-1 for every project at quote stage.
How MegaDome Handles It
The arched truss profile sheds dry snow continuously through the winter. For wet, sticky or accumulated snow, the truss is engineered with safety factors well above the OBC minimum. HP and XP series frames handle Ontario's heaviest snow zones without internal posts.
When You Need to De-Snow
In severe storm events that exceed the design load, manual snow removal may be required. MegaDome publishes monitoring guidelines for every building based on its design Ss. In 25 years of Ontario installs, structural failures from snow are essentially unheard of when the building is loaded per design.
- Monitor accumulation after any single-event storm exceeding 30 cm
- Clear drift accumulations at endwalls and equipment cover
- Keep ridge vents clear of ice dams
Why Steel Buildings Fail in Snow More Often
Flat or low-slope steel roofs accumulate drift loads that exceed design. MegaDome's 6/12+ pitch arch profile sheds before drift loads ever build up.
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