scope:

Introduction

The purpose of this Guide is to help Code users understand and apply the provisions in Part 9 of the National Building Code of Canada 2015 (NBC). It is a companion document to NBC Part 9-not a stand-alone document.

This Guide has no legal status and is not intended for formal adoption: its purpose is solely informational. Sketches and diagrams illustrate principles only; other methods of satisfying the requirements may be equally valid. If there are cases where text in the Guide conflicts with a requirement in the NBC, the NBC requirement governs.

Structure

The Guide discusses each Article of NBC Part 9 in turn in Code order through the use of text, illustrations, tables and examples. However, some sections of the Guide cover topics that span multiple Articles.

Each discussion starts with a general statement about the purpose of the Article in question. These general statements are not meant to summarize or paraphrase the content of the "Supplement to the NBC 2015: Intent Statements," which contains detailed statements on the specific intent of each NBC provision

Units of Measurement

Although the NBC only provides measurements in SI units, the Guide, in many cases, also shows corresponding imperial units in parentheses. Surveys indicate that people involved in all aspects of the housing industry still use imperial units, while those involved in the design and construction of small, non-residential buildings rely almost exclusively on SI units.

The SI measurements presented for the spacing of framing members and for the dimensions of products like wood-based panels are soft conversions, not actual conversions, of the actual imperial measurements (see NBC Note A-9.4.2.1.(1)). For example, 300, 400 and 600 mm joist and stud spacings are subdivisions of a floor or wall panel size of 1 200 × 2 400 mm. These SI measurements are soft conversions of the standard imperial 12, 16 and 24 in. spacings, and 4 × 8 ft. panel size, respectively. It is assumed that framing members will be spaced according to the actual metric conversions so that they align with the edges of sheathing materials, which are typically sized using imperial units.

For dimensions that are in effect Code requirements, such as minimum hallway widths, hard conversions of the SI measurements are presented, in which the imperial measurement is rounded up or down as required. The SI measurement is the legal requirement. The imperial measurement, which may be slightly different, is provided for convenience as an approximation of the SI requirement.

A conversion table for imperial equivalents of the most common SI units used in building design and construction is located at the end of the Guide.

Use of Illustrations

The illustrations explain general concepts and principles as well as key features of construction methods and technologies: they are not meant to be used as design or construction drawings. Many drawings focus only on one of many possible solutions. Most drawings highlight key features addressed in the surrounding text and show other construction details in the background. Although efforts have been made to show Code-compliant construction, it is important to note that the illustrations are not to be used as acceptable solutions to Code requirements.

Referenced Standards

The applicable editions of the standards referenced in the Guide are the editions referenced in the NBC 2015, including any updates to those standards published by Codes Canada.