Choosing Cumaru Decking Board Widths for Your Layout

Cumaru Decking: Available Board Widths

Cumaru decking is typically available in a few common widths, allowing for design flexibility. The most common nominal widths are 1x6 and 5/4x6. These nominal sizes refer to the rough dimensions before milling. The actual, finished dimensions are slightly smaller.

For Cumaru, a nominal 1x6 board typically finishes at 3/4 inch thick by 5.5 inches wide. A nominal 5/4x6 board typically finishes at 1 inch thick by 5.5 inches wide. These specific dimensions are crucial for accurate project planning and material calculations.

Both profiles offer the inherent benefits of Cumaru, including its natural resistance to insects, rot, and fungi, and a Class A fire resistance rating. The choice between them often comes down to the desired thickness and the visual preference for board width in your specific design. The 5.5-inch finished width is a versatile option that balances classic decking aesthetics with efficient material use.

Visual Impact of Board Width

The width of your Cumaru decking boards can dramatically alter the perception of your deck's size and style. Wider boards tend to create a more expansive, contemporary look, with fewer seams across the deck surface. This can make a smaller deck appear larger and less 'busy.'

Conversely, narrower boards, while not a standard offering for Cumaru in the same way as other species, would historically create a more traditional or intricate pattern. However, with the standard 5.5-inch finished width, Cumaru provides a balanced visual that works well in many settings. The consistent width allows for a clean, uniform appearance that highlights the wood's distinctive grain and natural color variations, which can range from a reddish-brown to a more golden tan.

Consider the overall scale of your outdoor space and the architectural style of your home. A large, open deck might benefit from the broad, uninterrupted lines that 5.5-inch wide boards provide, while a more compact area can still feel spacious with this standard width due to its balanced proportion.

Planning for Decking Board Quantity and Layout

Accurately calculating the number of Cumaru decking boards needed requires careful measurement of your project area and consideration of the chosen board width, along with any necessary spacing between boards. The finished width of 5.5 inches is your key dimension for these calculations.

When laying out your deck, consider how the board width interacts with the overall dimensions of the deck. Try to minimize cuts and waste where possible. However, most decks will require some boards to be cut.

It's always recommended to order slightly more material than your exact calculation to account for cuts, potential defects, or future repairs. A common practice is to add 10-15% to your total board footage calculation as an contingency.

Worked Example: Calculating Cumaru Board Quantities for a Deck

Let's consider a hypothetical rectangular deck measuring 12 feet wide by 20 feet long.

First, convert all measurements to a consistent unit, such as inches. The deck width is 12 feet * 12 inches/foot = 144 inches.

Since you cannot have a fraction of a run, you will need 26 full board runs across the width. This means 26 boards will be laid, with the last board potentially needing to be ripped down to fit the remaining space.

Each board will be 20 feet long. So, the total number of linear feet needed is 26 boards * 20 feet/board = 520 linear feet. Cumaru boards are available in lengths from 3 to 24 feet. For a 20-foot deck, ordering 20-foot or longer boards would be most efficient to minimize seams. If 20-foot boards are purchased, you would need 26 boards.

Always confirm the exact finished dimensions and recommended spacing from your supplier before finalizing your order. This example illustrates the process, but specific product details are paramount.

Considering Thickness: 1x6 vs. 5/4x6 Cumaru Decking

While both 1x6 and 5/4x6 Cumaru decking profiles typically share the same 5.5-inch finished width, their difference in thickness is a functional consideration. The 1x6 profile finishes at 3/4 inch thick, while the 5/4x6 finishes at 1 inch thick.

The thicker 5/4x6 board offers slightly increased stiffness and a more substantial feel underfoot. It may also be preferred for decks that anticipate heavier loads or for projects where a more robust appearance is desired. For most residential decking applications, either thickness can be suitable, but the choice can depend on your specific structural requirements, local building codes, and personal preference.

Ensure your subframe and joist spacing are appropriate for the chosen decking thickness. Always consult with a professional or refer to manufacturer guidelines and local building codes for proper installation to ensure structural integrity.

Before you order

• Confirm the exact finished width of the Cumaru decking profile you intend to purchase (e.g., 5.5 inches).
• Measure the precise dimensions (width and length) of your deck project area.
• Calculate the number of board runs needed across the deck's width, accounting for board width plus gap.
• Calculate the total linear footage required for the deck surface.
• Factor in a waste allowance (e.g., 10-15%) for cuts and potential imperfections.
• Consider the aesthetic impact of the board width on your specific deck size and design.
• Decide between 1x6 (3/4" thick) and 5/4x6 (1" thick) profiles based on structural needs and desired feel.
• Verify that your joist spacing is appropriate for the chosen decking thickness and spans.

Confirm installation details, approved uses and warranty terms in the current instructions for the exact product and profile. Your installer should verify the substrate, structure and applicable project requirements.

Questions to help you decide

Keep planning your project