OBC Firewall & Fire Spread Regulations: A Guide for Residential Construction in London, Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"The 1-hour fire-resistance rating exception for side-by-side residential units is a game-changer for cost-effective semi-detached and secondary suite developments in London and Oakville. At empcontracting.ca Inc., your construction contractor in London, Ontario, we emphasize the importance of the 'continuous protection' clause, ensuring that fire separations are properly sealed at the roof deck to pass framing and fire inspections with ease."
Navigating the 2024 Ontario Building Code (OBC) is essential for safe and compliant building practices. As the team at empcontracting.ca Inc., your construction contractor in London, Ontario, we specialize in interpreting complex sections like 9.10.11 regarding firewalls and fire spread prevention.
Section 9.10.11: Understanding Firewall Requirements
In Ontario, a party wall located on a property line must generally be constructed as a firewall. However, the OBC provides specific relief for residential occupancies to streamline construction without compromising safety.
9.10.11.2. Exceptions for Residential Firewalls
A full firewall is not required for residential buildings if the party wall is constructed as a fire separation with at least a 1-hour fire-resistance rating, provided it separates:
- Two dwelling units where no unit is located above another.
- A dwelling unit and a house containing a secondary suite.
- Two houses that both contain secondary suites.
This separation must be continuous from the top of the footings to the underside of the roof deck, with any gaps tightly filled with mineral wool or noncombustible materials.
9.10.11.4. Firewalls in Detached Garages
For detached garages that share a party wall on a property line, the OBC requires a fire-resistance rating of no less than 45 minutes.
Section 9.10.12: Preventing Fire Spread
Termination of Floors and Mezzanines
To prevent the vertical spread of fire, floor areas or mezzanines must terminate at an exterior wall, a firewall, or a vertical fire separation. Mezzanines may be exempt if they are not classified as a storey under specific OBC articles (9.10.4.1. and 9.10.4.2.).
Skylight Placement and Safety
To mitigate fire hazards between compartments, skylights cannot be placed within 5 meters of windows in an exposed wall if the adjoining roof of a separate fire compartment is not sprinklered.
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.