Understanding BC Building Code Rafter Span Tables
The BC Building Code, also known as the British Columbia Building Code, is a critical resource for anyone involved in construction or renovation projects in the province. One of the key aspects of this code is the regulation of rafter spans, which are crucial for the structural integrity and safety of buildings. This article aims to provide a comprehensive guide to understanding and navigating the BC Building Code rafter span tables.
Why Are Rafter Spans Important?
Rafters play a pivotal role in supporting the weight of a building's roof and transferring it to the exterior walls. The span of a rafter, which is the distance between two supports, directly impacts its load-carrying capacity. Therefore, it's essential to ensure that rafter spans comply with the BC Building Code to guarantee the safety and longevity of a structure.
What Are the BC Building Code Rafter Span Tables?
The BC Building Code provides tables that outline the maximum allowable rafter spans for different roof loads and rafter sizes. These tables are designed to help builders, architects, and engineers determine the appropriate rafter size and spacing for a given roof load. They are based on scientific calculations and extensive research, ensuring that structures built according to these guidelines are safe and durable.
Key Factors in BC Building Code Rafter Span Tables
- Roof Load: This refers to the total weight of the roof system, including the roof covering, insulation, and any additional loads such as snow or wind.
- Rafter Size: The size of the rafter, typically measured in inches, affects its load-carrying capacity. Larger rafters can span greater distances than smaller ones.
- Rafter Spacing: The distance between rafters, measured from the center of one rafter to the center of the next, also impacts the load-carrying capacity of the roof system.
Navigating the BC Building Code Rafter Span Tables
To use the BC Building Code rafter span tables effectively, you'll need to know the total roof load and the size of the rafters you plan to use. Once you have these values, you can find the maximum allowable rafter span in the table. Here's a step-by-step guide:
- Determine the total roof load in pounds per square foot (psf).
- Identify the size of the rafters you plan to use, measured in inches.
- Locate the row in the table that corresponds to your roof load and the column that corresponds to your rafter size.
- Read across to the column headed "Maximum Span" to find the maximum allowable rafter span for your specific roof load and rafter size.
Example: Using the BC Building Code Rafter Span Tables
Let's say you're planning a residential construction project in British Columbia with a roof load of 20 psf and you've decided to use 2x10 rafters. According to the BC Building Code rafter span tables, the maximum allowable span for these rafters under this roof load is 16 feet. This means that you can space your rafters 16 feet apart and still comply with the BC Building Code.
When to Consult a Professional
While the BC Building Code rafter span tables are a valuable resource, they are not a substitute for professional advice. If you're unsure about any aspect of your construction project, it's always a good idea to consult with a licensed architect or engineer. They can provide personalized advice and ensure that your project complies with all relevant building codes and standards.
Staying Up-to-Date with Changes to the BC Building Code
The BC Building Code is periodically updated to reflect advances in building science and technology. It's important to ensure that you're using the most recent version of the code when planning your construction project. You can find the latest version of the BC Building Code on the provincial government's website, along with other valuable resources for builders and homeowners.
In conclusion, understanding and using the BC Building Code rafter span tables is a critical part of ensuring the safety and longevity of any construction project in British Columbia. By following the guidelines outlined in this article, you can make informed decisions about rafter spans and ensure that your project complies with the BC Building Code.
More Details
British Columbia Building Code 2018. Division B. Span Tables. Table 9.20.17.4 ... (3) If floor joists span the full width of the building without support ...
Lintel spans may be increased by 5% if rafter and joist spans are no greater than 4.3 m and roof truss spans are no greater than 8.6 m. Spans may be increased ...
These span tables are taken from the National Building Code of Canada, 1998 BC Edition (current edition) and are for reference only.
12.05.2025 ... ... joists sizes using the British Columbia Building Code (BCBC). Note: The BCBC span tables are essentially the same as the National Building ...
24.11.2023 ... and Appendix C of Division B of the. 2018 Code. 3. Page 5. Table of ... Span Book. A-9.23.4.2. CWC. 2014. Engineering Guide for Wood Frame.
18.07.2012 ... 46 p. · Codes & guides · 1975 · National Research Council Canada. Associate Committee on the National Building Code.
BC Calc® performs engineering analysis to help our customers size beams, joists, columns, studs and tall walls for their building projects. It is simple to use, ...
SECTION 2 SPAN TABLES FOR WOOD JOISTS, RAFTERS AND. BEAMS ... roof trusses described in Part 9 of the National Building Code of Canada 1977. The Tables ...
The design of rafter spans is permitted to be in accordance with the AWC STJR... New York City Building Code 2022 > Chapter 23 Wood > Section BC 2306 Allowable ...
27.10.2024 ... ... BC BUILDING CODE-PART 9 SINGLE FAMILY DWELLING BUILDINGS Module 23 Section 9.23 ... rafter spacing, snow load and width of the building.
(joists and beams) can usually be selected from span tables in the Code. Framing members are highly influenced by wood species, preservative treatment ...
Building Code of Canada. Canadian Commission on Building and Fire Codes ... 2) Spans for floor joists that are not selected from Span Tables 9.23.4.2.-A.
15.01.2026 ... The code is straight forward and if he violated it you'll have no problem proving that. If you double up joists, it's gonna be a bitch bc of all ...
18.03.2023 ... You can find tables in the Ontario Building Code, which is available online. ... Because of that, here in temperate BC, regardless of the span, ...
Code & Standards · Energy & Environment · Economic Impact Map · Fire Service ... 2005 Span Tables for Joists and ...
a) the spans for roof joists and rafters in Span Tables 9.23.4.2.-D to 9.23 ... British Columbia Building Code 2018. Division B. 9.23.10.2. Bracing and Lateral ...
These joist span tables are taken from the National Building Code of Canada, 1998 BC Edition (still current) and are for reference only.
29.04.2025 ... Parowan Timber Beam. https://awc ...
Analyze multiple span joists with BC CALC® sizing software if the length of any ... Refer to the building code evaluation report or the. BC CALC® software.
(1) Except as required in Sentence (2) and Article 9.23.13.10., the spans for wood joists and rafters shall conform to the spans shown in Tables A-1 to A-7 for ...
