Cumaru Decking

Species: Dipteryx odorata

Cumaru decking (Brazilian Teak) can take some time to dry properly due to its propensity to shrink when freshly cut, but does have good stability characteristics once dry. Cumaru hardwood (Real Cumaru) is resistant to insect attack and decay. Our friends in South America have been using this hardwood lumber for fence posts and earth contact timbers for generations and brag about its useful life of 100 years. Cumaru is one of the densest woods on the planet and is VERY durable, which makes it ideal for deck building. It is common for a Cumaru tree to reach to 160 feet in height with a trunk diameter of 40 inches.

Other Names and Species:

Almendrillo, Amburana, Brazilian Teak, Cumaru Rosa, Imburana de Cheiro, Tonka, Tonka Bean, Tonquin Bean cumaru decking for building

Cumaru Origin:

Central and South America


The sapwood of red cumaru hardwood – RealCumaru – hardwood decking lumber is very similar to the heartwood, which ranges from red brown to deep red in color with a tight, even grain. Over time the red cumaru color will "flatten out" slightly. The species has an irregular, slightly interlocked grain and is coarse and wavy in texture. This dense, attractive Brazilian hardwood has the characteristics of ipe, but without the olive-green tone. Cumaru hardwood – RealCumaru - is sometimes referred to as Brazilian teak or southern chestnut.

Drying & Shrinkage

Cumaru hardwood is very unstable when used in dry climates and it is prone to shrinkage. It is naturally seasoned and kiln dried as to prevent shrinkage.

Janka Hardness:

3540 Cumaru decking (Real Cumaru) lumber is only two and a half percent softer than ipe(Brazilian walnut), almost 3 times as hard as Red Oak (1210 Janka).


A Cumaru decking (Real Cumaru) is constructed of one of the hardest woods on the planet. Cumaru hardwood is difficult to saw and bore and will have a fairly high blunting effect on tools. Where severely interlocked grain is not present, the wood planes to a smooth surface. Because of its high density and oily nature, the wood glues poorly. It nails and screws well; pre-boring is necessary. The dust arising from working Cumaru wood flooring has been known to cause a slight allergic reaction on contact with skin for some people, and as such some care should be taken in installing and preparing this product.


Cumaru hardwood naturally weathers to a beautiful, silver-gray patina. To maintain this rich tone, Messmer’s deck oil with UV inhibitor works best. Application of deck sealers is optional.


Like all lumber supplied by Brazilian Wood Depot, Cumaru Decking meets high standards for social, economic and environmental responsibility.  Visit RealWood.Org for more information about how purchasing this hardwood lumber fuels the economic value and preservation of the South American forests.

Deck Installation:

Joists and support beams - Pressure treated (PT) pine lumber is most often used for joists, beams and posts underneath Cumaru hardwood decking because it is cheap and is protected from weather by the Cumaru deck.  This protection extends the expected life of the support lumber dramatically.

Fasteners - After choosing the hardwood decking species that you prefer, a decision must be made on using screws through the face of the board or a type of hidden fastener that conceals the screws. The hidden fasteners cost a little more but many feel that spending a little extra for the beauty of hidden fasteners is a good investment since the deck will last a lifetime.

Deck Railings - There are many choices to make when designing your railings and balusters (vertical pickets).  Vertical balusters are more desirable than horizontal balusters (like cable) because of safety and ease of installation. Horizontal balusters enable children to scale the deck railing and require precise tautness to prevent children from squeezing between them. BW Depot stocks wood balusters that match the Cumaru decking and last a lifetime unlike PT or cedar balusters. Aluminum and galvanized steel balusters are beautiful cost effective choices and can be mounted with matching hardwood rails, posts and handrail. Galvanized steel railing baluster sections are much easier to install, much stronger and possibly the most cost effective option. The Fortress Iron provides these steel railing sections at a fraction of the cost of having them custom made. Matching Cumaru deck handrails and posts go well with any railing choice.

Ventilation - When planning the layout of your Cumaru deck, be sure that you allow for ventilation under your deck boards. This will ensures long life and extended beauty of your deck.

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