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
- “Header-Wrap” Air Barrier
- For
- builder
- Building types
- All building types
- Pages
- 3
Overview
Markham's Builder Tip Issue No. 21, linked as the “Header-Wrap” Air Barrier tip among the City's housing tips under the 2024 Ontario Building Code and dated January 1, 2025. It quotes Articles 9.25.3.1. to 9.25.3.3. on the air barrier system, its properties and continuity, including Sentence (5.1) on sealing or lapping a header wrap to the wall air barrier above and below. The Objective identifies the foundation-to-floor-header junction as a major leakage point under stack effect and covers sealing seams and corners with acoustical sealant or sheathing tape.
What it covers
- 9.25.3.1. Required Barrier to Air Leakage
- 9.25.3.2. Air Barrier System Properties
- 9.25.3.3. Continuity of the Air Barrier System
- Objective
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