MarkhamBuilding InspectionsInspections

Duct Sealing For Dwellings

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: Duct Sealing for Dwellings
For: builder
Building types: All building types
Pages: 2
Instruments: SMACNA, HVAC Duct Construction Standards – Metal and Flexible

Overview

The City of Markham's Builder Tip No. 78, dated January 1, 2025, on sealing heating and cooling ducts in houses, filed with the City's housing tips under the 2024 Ontario Building Code. It quotes the defined term conditioned space and Sentences 9.33.6.7.(8) to (10) on RSI 2.1 duct insulation in unheated spaces, Class A sealing of ducts in unconditioned space or outdoors, and Class C sealing of supply ducts in conditioned space under the SMACNA HVAC Duct Construction Standards. A diagram shows a Class A sealed duct.

What it covers

Division A – Part 1
1.4.1.2. Defined Terms
9.33.6.7. Installation of Ducts and Plenums
Objectives

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