MarkhamBuilding InspectionsInspections

Permitted Openings In Wall & Ceiling Assemblies

Published by City of Markham

This is the City of Markham’s document, as published on its website on 18 October 2026. The municipality may have changed it since: check the current version at the source. Legal notice

Type: Guide
Published by: City of Markham
Date: January 1, 2025
Also called: Permitted Openings in Wall Assemblies
For: builder
Building types: All building types
Pages: 2
Instruments: MMAH Supplementary Standard SB-3, Fire and Sound Resistance Tables · MMAH Supplementary Standard SB-2, Fire Performance Ratings

Overview

Markham's Builder Tip No. 70, dated January 1, 2025 and updated to the 2024 OBC, linked on the City's Builder Tips page as permitted openings in wall assemblies and filed with the housing tips under the 2024 Ontario Building Code. It quotes Article 9.10.5.1., Permitted Openings in Wall Membranes, on electrical outlet boxes in fire-rated wall and ceiling membranes, offset boxes on both sides of a wall, and duct openings in ceilings rated under SB-3 and SB-2. Its objective describes gypsum board between outlet boxes in one stud space.

What it covers

9.10.5.1. Permitted Openings in Wall Membranes
Objective

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