2024 Ontario Building Code: Expert Guide to Floor Waterproofing and Soil Gas Control
Sarah's Expert Insight
OBC Compliance Specialist
"In areas like London and Oakville, soil gas mitigation is a critical safety component due to varying radon levels across Southwestern Ontario. As a senior consultant at empcontracting.ca Inc., your construction contractor in London, Ontario, I emphasize that the subfloor depressurization rough-in is one of the most cost-effective 'insurance policies' a builder can install to ensure long-term indoor air quality and compliance with the latest 2024 standards."
When navigating the complexities of the 2024 Ontario Building Code (OBC), specifically Section 9.13, professional oversight is essential. At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize structural integrity and environmental safety through meticulous adherence to waterproofing and gas ingress standards.
Section 9.13.3.5: Floor Waterproofing Systems
For high-moisture environments, the OBC mandates a specific layered approach to basement floors-on-ground. To achieve compliance, a membrane waterproofing system must be sandwiched between two distinct layers of concrete. Each concrete layer must be at least 75 mm thick. Crucially, this floor membrane must be continuous with the wall membrane to ensure a complete, airtight, and watertight seal.
Section 9.13.4: Soil Gas and Radon Control
Addressing the movement of hazardous gases from the ground into living spaces is a core focus of modern construction. Subsection 9.13.4 applies to all assemblies (walls, roofs, and floors) separating conditioned space from the earth.
Mandatory Protection and Polyethylene Standards
Except for unenclosed areas like garages, all assemblies in contact with the ground must resist soil gas leakage. If polyethylene is utilized as the barrier, it must meet the CAN/CGSB-51.34-M standard. This ensures that the material is durable enough to function as an effective vapour barrier throughout the building's lifecycle.
Radon Extraction Rough-Ins
For residential occupancies, the code now requires a rough-in for a subfloor depressurization system. This future-proofs the building, allowing for the easy installation of a radon extraction system if gas levels become problematic. This involves a gas-permeable layer (often granular material) and a dedicated pipe system to allow for effective depressurization of the sub-slab environment.
Professional Implementation
Selecting empcontracting.ca Inc. your construction contractor in London, Ontario, ensures that these technical requirements—from granular material selection to inlet placement—are executed with precision, safeguarding your property against radon and water damage.
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.