OBC DIVISION B · PART 9 · SECTION 9.38 — LOG CONSTRUCTION

What are the code requirements for log walls in Ontario?

Log walls must use sound, adequately sized logs shaped and fitted so joints shed water, sealed between courses with gaskets or chinking, interlocked at corners, and detailed with weather protection, since the log wall serves as structure, cladding and air barrier together.

Code reference
Log construction must provide structural adequacy, weather resistance and air tightness through the log work itself: logs of suitable species and condition, longitudinal joints profiled and sealed to resist water and air leakage, corners interlocked for stability, and connections and openings detailed to accommodate the distinct behaviour of solid-timber walls, including protection from ground and roof moisture.
OBC Division B, Section 9.38.

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

A log wall does four jobs at once, so the joinery is everything. Scribed or milled joints need continuous gaskets or quality chinking because air leakage, not conduction, is the typical energy weakness of log homes. Keep logs high off grade with generous roof overhangs, since bottom courses rot first. Checking, the cracks that open as logs season, is normal but should be oriented and sealed sensibly. Energy compliance usually runs through a performance path, and builders should engage designers experienced with log systems, as generic framing details rarely translate.

Plain language

In a log home the logs themselves are the wall, the siding and the air seal, so each joint must be shaped and sealed to keep out wind and rain. Good overhangs and height above ground keep the bottom logs from rotting.

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.