Ontario Deck Span Tables: Ultimate Guide for 2024

Understanding Ontario Deck Span Tables: A Comprehensive Guide

When embarking on a deck construction project in Ontario, it's crucial to understand the provincial building codes, particularly the deck span tables. These tables are not just a set of numbers but a vital tool that ensures the safety and longevity of your deck. This guide will delve into the intricacies of Ontario's deck span tables, helping you make informed decisions throughout your project.

What are Deck Span Tables?

Deck span tables, also known as joist span tables, provide maximum allowable spans for floor joists, deck joists, and beams based on the type of material used and the load they are expected to bear. They are designed to ensure that the structural components of your deck can safely support the intended loads without excessive deflection or failure.

Why are Ontario Deck Span Tables Important?

Ontario's building codes, based on the National Building Code of Canada, require that decks meet specific structural standards. Deck span tables are a key part of these standards, helping to prevent deck collapses and other structural failures. By adhering to these tables, you can ensure your deck is safe, durable, and compliant with provincial regulations.

Understanding Ontario's Deck Span Tables

Ontario's deck span tables are based on the type of material used for the joists and the spacing between them. The most common materials are wood and engineered lumber. The tables also consider the live load, which is the weight the deck is expected to support, typically 40 lbs per square foot for residential decks.

Wood Joists

For wood joists, the span tables consider the species of the wood, its grade, and the spacing between the joists. The most common species used in Ontario are Douglas Fir-Larch and Hem-Fir. The tables provide maximum allowable spans for different joist sizes, ranging from 2x6 to 2x12, and joist spacing, typically 12", 16", or 24".

Engineered Lumber

Engineered lumber, such as I-joists and LVL (Laminated Veneer Lumber), offers longer spans than solid sawn lumber. The span tables for engineered lumber are based on the size of the joist and its load rating. The most common sizes are I-joists with load ratings of 20, 30, and 40.

• I-Joists: Maximum allowable spans range from 12 to 24 feet, depending on the load rating and joist size.
• LVL: Maximum allowable spans range from 10 to 20 feet, depending on the size of the LVL and its load rating.

Factors Affecting Deck Span Tables

Several factors can affect the maximum allowable spans outlined in the deck span tables. These include:

• Deck Height: The higher the deck, the more the joists must span. Ontario's building codes require additional support for decks higher than 30 inches above grade.
• Load Combination: The tables assume certain load combinations. If your deck will bear unusual loads, you may need to consult an engineer.
• Local Soil Conditions: Poor soil conditions may require additional support for your deck's footings.

When to Consult an Engineer

While Ontario's deck span tables provide a solid foundation for designing your deck, there are times when you should consult a professional engineer. These include:

• When your deck will be higher than 30 inches above grade.
• When your deck will span more than 12 feet.
• When your deck will bear unusual loads or have unique design features.
• When local soil conditions are poor.

In conclusion, understanding and adhering to Ontario's deck span tables is crucial for building a safe, durable, and code-compliant deck. Whether you're using wood or engineered lumber, these tables provide the foundation for a solid deck design. Always remember, when in doubt, consult a professional engineer.