Tropical decking materials are often unbeatable when it comes to durability, density, beauty, and other desirable characteristics. Yet despite experiencing steady and increasing popularity, tropical decking lumber species such as Ipe and Cumaru have some unique characteristics of which builders need to be aware.
1. Compensating for Quartersawn Issues
Most tropical decking lumber is quartersawn. Such sawing increases the stability of exterior lumber and showcases consistent vertical grain striping on the face. At the same time, though, this sawing technique means that medullary rays, which are part of the internal structure of the tree, become exposed. These dense areas resist planing and are rougher than other parts of the wood, sometimes requiring touch-up sanding in order to achieve smoothness. While other hardwoods may display similar issues, the extremely hard species used for tropical decking can make them more noticeable.
2. Reducing Potential for Warping
Decking products by nature contain higher moisture levels than lumber used for interior applications. Tropical decking products are air dried, rather than kiln dried, which leaves them in a moisture range between 14 and 18 percent. Such moisture levels are necessary for outdoor stability, as lower moisture levels achieved by kiln drying lead to thirsty boards that soak up moisture the first time they’re exposed to rain or high humidity.
Higher moisture content helps prevent rapid expansion when the wood is exposed large swings in moisture levels; however, different climates require an acclimatization period. In order to ensure that your decking boards do not warp after they’re installed, it’s important that you store the lumber for 2-3 weeks in the same climate as the job site, out of direct sunlight and with good air flow. This acclimatization period may produce up to 1/8” change on boards only 4” wide, or ¼” on 6” boards. Such movement is clearly preferable before the wood is screwed into place.
3. Preventing Continued Movement
After the recommended acclimatization period, there are steps you can take to avoid unnecessary movement. Once the tropical decking boards have been installed, movement over the lifetime of your deck can be reduced through providing ground side ventilation and proper end sealant. Ventilation promotes air flow, which leads to even expansion and contraction throughout seasonal changes in moisture levels.
Proper end sealant can also be used when the boards are cut to length. Because freshly exposed end grain is the easiest way for moisture to enter the board, unsealed ends can produce rapid changes in moisture, causing unsightly splitting and checking. Such moisture changes can be slowed by products like Anchorseal.
4. Alleviating Tool Trauma
Many tropical decking species are extremely dense and hard, and your tools will need to be prepped accordingly. The lumbers’ hardness means that you’ll need very sharp tools, and the woods’ high density can lead to splitting if you fail to pre-drill. Unlike pressure-treated material that compresses easily, these lumber species require larger holes and a lot of man power. Because these tropical species are 6 times harder than pressure-treated pine, drilling into these woods requires heavy-duty drills. Be sure to prepare for this by allotting extra time and labor, as well as extra drill bits.
It’s essential that you come to your tropical decking project with a clear view of what it will entail and how to prevent common pitfalls from tainting your experience. Despite the above-listed common issues, tropical lumbers are still your best choice when it comes to decks and other outdoor projects. For more information on these woods and how to incorporate them into your next project, contact McIlvain Lumber Company today. With over 200 years of experience in the lumber industry, no lumber wholesaler is better equipped than McIlvain to answer your lumber-related questions and to supply you with the wood you need. To learn more about what sets McIlvain apart and to see their extensive inventory of domestic and exotic hardwoods and softwoods, visit their website today, or check out these selections from their lumber blog: