Cumaru

Dipteryx odorata

Cumaru Origins

Cumaru is a South American hardwood that has a beautiful yellow-brown color and a fine interlocking grain pattern. It is highly durable, rot resistant, and surprisingly cost effective compare to many other tropical hardwood species. The most common use for the hardwood is as a decking product and it is sawn and milled into S4S and E4E (surface on 4 sides and eased on 4 edges) decking boards in Brazil before being exported. Rough sawn lumber is also available but on a much smaller scale.

Cumaru Wood Characteristics

Character	Green	Dry	Units
Bending Strength	19295	27270	psi
Max Crushing Strength	9020	13720	psi
Impact Strength	–	39	inches
Stiffness	2690	3030	1000 psi
Hardness (Janka)	–	3450	lbs
Toughness	–	265	in-lbs
Specific Gravity	0.86	0.90	–
Weight	–	71	lbs/ft3
Density	–	71	lbs/ft3
Radial Shrinkage	–	5	%
Tangential Shrinkage	–	8	%
Volumetric Shrinkage	–	12	%

The raw lumber is often confused with Teak, and it is sometimes referred to as Brazilian Teak. In actuality it a very different wood and comes from the other side of the world, but does have much of the same weather resistance that makes Teak famous. The golden hue is also present so the Brazilian Teak name isn’t far off.

Despite these similarities, in its most common use, Cumaru wood is actually more of an alternative to Ipe or Massaranduba than to Teak, because of its extreme hardness and weather resistance making it perfect for decking and siding. The wood dries evenly and is only slightly prone to checking if dried properly. It is a dense species with an interlocking grain, but it planes and machines quite well. Though a relatively stable species, we have found that it is best to use it in a thicker cut for ideal results. Therefore, J. Gibson McIlvain only carries 5/4 thickness for decking. We stock both 4 and 6 inch wide deck boards that are surfaced and eased on 4 sides. We can also groove your decking for use with hidden deck fasteners.

An oily wood and often it has a waxy texture. This high oil content makes the decking very resistant to the elements. Although the oil can occasionally cause problems with finishing or gluing, an easy pretreatment can strip away this oil and prepare the wood nicely for the finishing and gluing processes. It is not the cheapest decking product, but it is also not the most expensive. As such, it makes a great alternative to Ipe decking, while still pleasing discerning customers who fear confronting the potential stability issues that plague the cheapest of tropical decking options.

Cumaru Siding

As a decking wood, it excels with high hardness, great strength, and reliable stability. These same properties make it an excellent choice for exterior siding and rain screen siding applications. The same sizes of boards used in decking can easily be run vertically up a wall or even milled for tongue and groove ceiling or porch flooring applications. Despite the extremely common usage for decking, it is first and foremost a great exterior species and can be used for anything from siding, to docks, to outdoor furniture.