Joist Basics When it comes to planning your outdoor decking project, one of the key considerations is selecting the right board dimensions. Whether you’re embarking on a brand-new project or replacing boards on an existing deck, getting the dimensions right is crucial. Let’s dive into the essentials, starting with joists.
Joists serve as the backbone of your deck’s framework. If you’ve ever glanced beneath a wooden deck, you’ve observed the intricate network of joists that provide structural support. These joists are typically vertically oriented for maximum strength and securely fastened to your home at one end. Decking boards are affixed on top of these joists.
To ensure stability, ease of installation, and an aesthetically pleasing look, joists are usually evenly spaced out to distribute the load. Determining the size and spacing of joists is a critical safety matter and should be calculated with professional guidance.
Board Dimensions Now, let’s turn our attention to the boards themselves. Outdoor decking boards are available in various dimensions, but the most common sizes are 19×90, 21×145, and 28×145, which originate from standard sawn sizes (25×100, 25×150, and 32×150).
Considering Strength Two main factors determine the required board width: timber strength and joist spacing. The strength, in this context, is measured by the distance a deck board can span between two joists. Wider joist spacing calls for sturdier decking boards. Keep in mind that different wood species offer varying levels of strength.
Softwoods like treated pine and western red cedar are generally less robust but easier to work with. In contrast, hardwoods like Cumaru are exceptionally strong but may require more woodworking skill during installation or adjustments.
Durability Matters Another crucial aspect to consider is durability, measured in the number of years your decking and joists will remain safe to use – also known as their service life. For instance, pine is not particularly durable, and it’s prone to rot without treatment. This is why it’s commonly treated with chemicals to extend its lifespan. On the other hand, naturally durable timbers like Ipe don’t require chemical treatment and can last for many years without any additional measures.
The Downsides of Composite
While composite decking materials have gained popularity, it’s worth noting that they are not made of wood, and concerns about the ecological impact of chemicals and plastics have surfaced. Additionally, composite boards can become dry and brittle, necessitating closer joist placement to prevent flexing. This can lead to unsightly “deck gullies” and frequent cracks or breaks in the boards.
Width Matters
Many people may view board width as purely a matter of aesthetics or cost, but it also plays a crucial role in dimensional stability. Narrower decking boards tend to have less movement, which is important for long-term durability.
In Summary
Selecting the right dimensions for your outdoor deck is a vital step in your project planning. We hope this information has been valuable in guiding your decisions. You can explore the range of decking products we offer on our website.
