Ontario Building Code 2024: Cladding Fasteners and Furring Standards (Section 9.27.5.4)
Sarah's Expert Insight
OBC Compliance Specialist
"In high-wind regions like Muskoka or the exposed corridors of Oakville, adhering to the 400mm fastener spacing for vinyl and metal cladding is not just about code—it is vital for preventing 'blow-offs' during seasonal storms. At empcontracting.ca Inc. your construction contractor in London, Ontario, we prioritize Table 9.27.5.4.-A compliance to ensure that the building envelope remains airtight and durable against Ontario’s harsh freeze-thaw cycles."
When installing exterior finishes, compliance with the 2024 Ontario Building Code (OBC) is essential for structural integrity and weather protection. Section 9.27.5.4 outlines the specific requirements for furring, fastener size, and spacing for various types of cladding and trim.
Requirements for Furring Without Sheathing
In applications where furring is applied without sheathing, the OBC mandates specific lumber dimensions to ensure adequate support:
Lumber Dimensions and Support Spacing
- 19 mm by 64 mm lumber: Required on supports spaced at a maximum of 400 mm o.c.
- 19 mm by 89 mm lumber: Required on supports spaced at a maximum of 600 mm o.c.
Regardless of dimensions, all furring must be securely fastened to the structural framing and maintained at a maximum spacing of 600 mm o.c. to prevent buckling or detachment.
Fastener Specifications for Cladding and Trim
According to Table 9.27.5.4.-A, the attachment of cladding to wood framing or furring must follow strict fastener length and spacing rules to resist environmental loads.
Wood, Metal, and Vinyl Siding Requirements
- Wood Trim and Lumber Siding: Minimum nail length of 51 mm with a maximum spacing of 600 mm o.c.
- Vinyl Siding: Horizontally applied vinyl requires 38 mm fasteners at 400 mm o.c., whereas vertically applied vinyl requires a tighter 300 mm o.c. spacing.
- Metal Cladding: Must be nailed to framing with 38 mm fasteners at 600 mm o.c., or 400 mm o.c. if nailed to sheathing only.
Shingles and Shakes
For wood shakes and shingles, the fastener count increases with the width of the unit. Shakes over 200 mm in width require a minimum of 3 nails or staples, while shingles of the same width follow the same numerical requirement but with a shorter 32 mm fastener length.
Flat Wall Insulating Concrete Form (ICF) Considerations
For modern builds utilizing ICF units, screw sizes and spacing must conform to Table 9.27.5.4.-B. This is specifically applicable in regions where the 1-in-50 hourly wind pressure (HWP) is 0.60 kPa or less. Ensuring these fasteners reach the web fastening strips is a critical step for envelope stability.
For expert installation that meets these rigorous standards, trust empcontracting.ca Inc. your construction contractor in London, Ontario, to handle your next exterior project.
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.