OBC 2024 Guide: Cladding Attachment to ICF Units for London, Ontario Contractors
Sarah's Expert Insight
OBC Compliance Specialist
"As high-performance ICF construction becomes the standard in London and Muskoka, ensuring cladding is secured directly into the internal web strips—rather than just the foam—is the most common failure point I see during inspections. At empcontracting.ca Inc. your construction contractor in London, Ontario, we emphasize that even in the lower wind-load zones of Oakville, adhering to the 6mm web penetration rule is non-negotiable for preventing siding blow-offs and moisture penetration."
Understanding the 2024 Ontario Building Code (OBC) requirements for cladding is essential for maintaining structural integrity and longevity. Whether you are working with Insulated Concrete Forms (ICF) or traditional framing, empcontracting.ca Inc. your construction contractor in London, Ontario, ensures all fastener specifications meet these rigorous provincial standards.
9.27.5.4. Attachment of Cladding to Flat Wall ICF Units
For installations where the 1-in-50 Hourly Wind Pressure (HWP) is less than or equal to 0.60 kPa, the following screw and spacing specifications apply for web fastening strips:
Specific Material Fastener Requirements
- Wood & Vinyl Trim: Minimum 3.5 mm screw diameter; 400 or 450 mm horizontal spacing.
- Lumber or Metal Siding: Minimum 4.2 mm screw diameter; 400 or 450 mm horizontal spacing.
- Masonry Veneer: Minimum 4.2 mm screw diameter; masonry ties must be screwed to web fastening strips.
- Panel-Type Cladding: For material up to 7 mm thick, use 3.5 mm screws at 150-200 mm spacing along edges. For thicker panels, use 4.2 mm screws at 300-400 mm spacing.
Note: Screws must be long enough to penetrate through the web fastening strips by a minimum of 6 mm.
9.27.5.5. - 9.27.5.7. General Fastener Standards
Corrosion Resistance and Material Compatibility
Per Section 9.27.5.5., all nails or staples used for cladding and wood trim must be corrosion-resistant and chemically compatible with the cladding material to prevent premature degradation.
Expansion, Contraction, and Penetration
Thermal movement is a critical consideration in Ontario's climate:
- Metal Cladding: Fasteners must be positioned to permit movement.
- Vinyl and Polypropylene Siding: Fasteners must be installed in the center of the nail hem slots to allow for expansion.
- Penetration Depths: Shakes and shingles require 19 mm penetration into framing; vinyl and polypropylene require 32 mm; most other cladding types require a minimum of 25 mm penetration.
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.