Ontario Building Code 2024 May 2026

If you are a homeowner reading this because you want to pull a permit for a garage or a basement apartment, the Ontario Building Code 2024 changes your game plan.

Based on updated climate data (1995–2020), the code has increased minimum design loads:

In response to catastrophic flooding in Toronto, Ottawa, and Windsor, the 2024 Code introduces mandatory flood-proofing measures. ontario building code 2024

Given the hype, it is important to note what remains the same in the Ontario Building Code 2024:

Previously, rural residential buildings had slightly relaxed standards. The 2024 Code largely harmonizes rural and urban requirements, specifically regarding septic systems and structural loads (snow and wind). If you are a homeowner reading this because

The Supplementary Standard SB-12 has been overhauled. For residential homes (Part 9 buildings), prescriptive thermal resistance (R-value) requirements have increased:

The Game Changer: Airtightness Testing New Part 9 residential construction must now undergo blower door testing, achieving ≤ 2.5 Air Changes per Hour (ACH) at 50 Pascals. This is a major step toward Passive House standards. The Game Changer: Airtightness Testing New Part 9

If you have existing drawings prepared under the 2012 Code, you are likely facing a "change of code" situation. Here is the checklist to avoid rejection:

One of the foundational aspects of the 2024 OBC is its alignment with the National Building Code of Canada (NBC). Historically, Ontario maintained distinct variations that created barriers for national designers and manufacturers operating in the province.

The 2024 edition adopts the National Research Council’s (NRC) objective-based format more thoroughly. This harmonization allows for:

However, the province has retained "Ontario-only" amendments where local context dictates, particularly regarding snow loads, seismic activity, and specific fire safety requirements for high-rise buildings.