We get the quandary: You want to save money, but you definitely don’t want to go too cheap. You need high-end decking, but Ipe isn’t within your budget. Well, Cumaru might be the perfect fit for your next decking project. Cumaru has many features similar to other popular tropical decking lumber species, such as Teak and Ipe, but we’d do it quite a disservice to consider this brilliant species to be only an alternative to other species. It has all the characteristics that make a species excellent for use as a decking product: weather resistance, beauty, and hardness.
Like its more famous neighbor, Ipe, Cumaru originates in South America (and primarily, Brazil). Because of the yellow overtones in one variant of freshly milled Cumaru, it’s often compared to Teak; in fact, it’s sometimes referred to as “Brazilian Teak” for its golden-tinted hues. Another similarity with Teak is its wonderful weather resistance. However, a more careful examination of this species’ characteristics will reveal that Cumaru actually bears more similarity to Ipe. Like Ipe, Cumaru is an extremely hard, dense species. In addition to the yellow variant that appears similar to Teak, Cumaru has a red variant that appears almost identical to Ipe. (The red variant is more likely to be used for decking.)
Cumaru’s Prize Characteristics
Like we mentioned earlier, Cumaru deserves to be considered on its own merits, rather than simply compared to other tropical species. The fine interlocking grain pattern of Cumaru highlights its gorgeous coloring, whether it includes yellow or red overtones. As long as Cumaru is properly dried, it isn’t likely to check. Despite its extreme density and interlocking grain, Cumaru machines and planes well. Overall, it’s an amazingly hard, dense, stable decking option.
While it isn’t as stable in thinner boards as some decking species may be, this issue can easily be overcome by using thicker cuts of Cumaru (5/4 thickness and thicker); the most popular widths are 4 and 6 inches. With careful kiln drying, these thicker cuts of Cumaru can become just as stable as Ipe. At only 2/3 the price of Ipe, Cumaru really is a bargain! The same oil content and waxy texture that allows Cumaru to resist rotting and insects can also cause problems with finishing or gluing; that issue can be assuaged with a pretreatment, stripping the oil from areas that require gluing.
The best Cumaru decking has been carefully kiln dried to eliminate shrinkage. Even still, if you happen to be in an extremely dry climate, using Cumaru can be a bit risky. For most of us, though, Cumaru is a crowd pleaser that allows you to save money without dealing with the stability problems that come with cheaper tropical decking products.