OBC Section 9.25 Guide: Insulation and Condensation Control with empcontracting.ca Inc. in London, Ontario
Sarah's Expert Insight
OBC Compliance Specialist
"Compliance with Section 9.25 is non-negotiable for projects in London and Muskoka, where extreme temperature differentials can cause rapid moisture accumulation within walls. As your construction contractor in London, Ontario, empcontracting.ca Inc. meticulously selects materials like CAN/ULC-S705.1 spray foam to provide superior air sealing and thermal resistance, protecting your investment from the risk of structural rot and mold."
Understanding the 2024 Building Code Compendium is essential for high-quality residential and commercial builds. As empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize the strict adherence to Section 9.25 regarding heat transfer and air leakage to ensure building longevity.
Scope and Application of Section 9.25.1.1.
Section 9.25 focuses on the control of heat, air, and water vapour transfer. The primary goal is to mitigate condensation that can damage structural integrity and indoor air quality.
Mandatory Building Envelope Components
According to the Ontario Building Code (OBC), all floors, walls, and ceilings that separate conditioned (heated/cooled) spaces from the exterior or unconditioned spaces must include:
- Thermal Insulation: Conforming to Subsection 9.25.2.
- Air Barrier System: Providing a continuous seal against air leakage (Subsection 9.25.3).
- Vapour Barrier: Controlling moisture diffusion through materials (Subsection 9.25.4).
Thermal Insulation Requirements (9.25.2.1.)
The code requires that insulation be sufficient to prevent moisture condensation on the interior surfaces during winter months while maintaining occupant comfort. This is a critical performance standard for the cold winters in London and Southern Ontario.
OBC Approved Insulation Materials
To remain compliant, materials used by your contractor must meet specific standards, including:
- Mineral Wool: ASTM C726 or CAN/ULC-S702.1.
- Polystyrene: CAN/ULC-S701.1 (Note: Type 1 cannot be used above roofing membranes).
- Spray Foam: CAN/ULC-S705.1 (Medium density rigid polyurethane).
- Cellulose Fibre: CAN/ULC-S703.
Insulation in Ground Contact
Any insulation in contact with the soil must be inert and moisture-resistant to ensure its R-value (insulative properties) is not degraded by groundwater or soil acidity.
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.