Code Library › Volume 1 › Section 9.25 — Heat Transfer, Air Leakage and
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.25.2.1.Required Insulation

(1) All walls, ceilings and floors separating heated space from unheated space, the exterior air or the exterior soil shall be provided with sufficient thermal insulation to prevent moisture condensation on their room side during the winter and to ensure comfortable conditions for the occupants. (See Note A-9.1.1.1.(1))
← Previous9.25.1.1. Scope and ApplicationNext →9.25.2.2. Insulation Materials

Common questions about this part of the code

What are the insulation installation requirements in the Ontario Building Code?What are the attic insulation rules for houses in Ontario?Does polyethylene have to go on the warm side of the wall in Ontario?

Understand this provision in seconds

BUILDAiD Assist explains any article of the building code in plain English — with exact citations, exceptions and related requirements.

Try BUILDAiD Beta

Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.