OBC 2024 Guidelines: Wood Furring and Gypsum Board Standards for London, Ontario Construction
Sarah's Expert Insight
OBC Compliance Specialist
"Correct furring spacing is the unsung hero of a level ceiling; skipping these OBC standards often leads to visible waviness and drywall cracking in the humid climates of London and Muskoka. At empcontracting.ca Inc. your construction contractor in London, Ontario, we meticulously follow Table 9.29.3.1 to ensure every interior finish remains stable and aesthetically perfect for decades."
Understanding the Ontario Building Code (OBC) is essential for high-quality interior finishes. As empcontracting.ca Inc. your construction contractor in London, Ontario, we ensure every project adheres to the rigorous standards of Section 9.29 for wood furring and gypsum application.
9.29.3. Wood Furring Specifications
Wood furring provides the necessary substrate for wall and ceiling finishes. According to OBC 9.29.3.1, the size and spacing of wood furring must strictly conform to Table 9.29.3.1 to ensure structural stability.
Size and Spacing Requirements
Furring size is determined by the spacing of supports. For example, if supports are spaced at 600 mm o.c., the minimum furring size increases to 19 x 89 mm for wider spacing to maintain rigidity. Standard 19 x 38 mm furring is generally acceptable for 300 mm spacing on continuous supports.
Fastening Guidelines
To ensure a secure bond, OBC 9.29.3.2 requires that furring be fastened to the framing or wood blocks using nails with a minimum length of 51 mm.
9.29.4 & 9.29.5. Plastering and Gypsum Board Application
The application of plaster and gypsum board is governed by both the OBC and specific CSA/ASTM standards to ensure fire safety and finish quality.
Gypsum Board Finish (Taped Joints)
Section 9.29.5 applies to single-layer gypsum board applications. It is crucial to note that applications on flat insulating concrete form (ICF) walls must conform to ASTM C840 standards, which is a common requirement in modern, energy-efficient builds in Ontario.
Material Standards and Fire Safety
All gypsum products must meet CAN/CSA-A82.27-M or ASTM C1396 standards. Specifically, the flame-spread rating must be determined in accordance with CAN/ULC-S102 to ensure the assembly meets provincial fire safety regulations.
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.