2024 Ontario Building Code Guide: Roof Assemblies and Mass Timber Fire Safety
Sarah's Expert Insight
OBC Compliance Specialist
"With the rise of mid-rise mass timber projects in London and Oakville, strictly following CAN/ULC-S126 and S107 standards is essential for both building permits and long-term insurance liability. At empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure that your roof assemblies and structural timber elements are meticulously specified to meet these 2024 fire-safety classifications."
Navigating the complexities of the 2024 Ontario Building Code (OBC) is critical for ensuring the structural integrity and fire safety of modern developments. As empcontracting.ca Inc. your construction contractor in London, Ontario, we specialize in implementing these technical requirements to ensure your project meets the highest safety standards.
3.1.13.12. Encapsulated Mass Timber Construction (EMTC)
In buildings utilizing encapsulated mass timber, flame-spread ratings are strictly regulated. Subsection 3.1.6 requirements apply to all surfaces, including those exposed by cutting through material in exits. Specific exceptions are made for doors, heavy timber construction, and fire-retardant-treated wood, ensuring that structural elements remain resilient under thermal stress.
3.1.14. Fire Safety in Roof Assemblies
Fire-Retardant-Treated Wood Roof Systems
According to OBC 3.1.14.1, any wood roof system treated with fire retardants must meet the conditions of acceptance found in CAN/ULC-S126. Furthermore, the supports for these decks must consist of noncombustible construction, heavy timber, or fire-retardant-treated wood to prevent the rapid spread of fire beneath the roof-deck assembly.
Metal Roof Deck Assembly Requirements
Metal roof decks supporting combustible materials must generally comply with CAN/ULC-S126 standards. However, exemptions are available under OBC 3.1.14.2 if the building is fully sprinklered, the roof has a 45-minute fire-resistance rating, or the combustible material is protected by a thermal barrier such as 12.7 mm thick gypsum board.
3.1.15. Roof Covering Classifications
All roof coverings in Ontario must have their fire classification determined in accordance with CAN/ULC-S107, 'Standard Method of Fire Tests of Roof Coverings.' This ensures that every material, from shingles to membrane systems, is tested for its ability to withstand external fire exposure.
Disclaimer: This content is generated from the Ontario Building Code for educational purposes. Always consult with a licensed professional engineer or your local building department before starting any construction project in London, Ontario.