Hardwood decking species
Cumaru Decking
Dipterix odorata, Southern Chestnut, Brazilian Teak
Cumaru (often sold as Brazilian Teak) is genuinely hard and a little cheaper than Ipe — but in our experience it’s prone to checking, warping, cupping and a lot of seasonal movement once it’s in service, which means callbacks and disappointed customers. It’s also CITES Appendix II, so it carries the same export-permit paperwork and supply swings as Ipe without Ipe’s stability or lifespan. For the money we’d steer you to Golden Balau (more stable, better value) or Ipe (the benchmark). We’ll source Cumaru on request, but we won’t pretend it’s our first choice.
Cumaru, sometimes sold as Brazilian Teak, is one of the densest decking hardwoods in regular supply — 3,200 lbf on the Janka scale at roughly 1,080 kg/m³. It is rated very durable, resists both brown- and white-rot fungi, and weathers exceptionally well, which is why it turns up on boardwalks and commercial decks as often as on houses.
Expect a reddish-brown to yellowish-brown board with interlocked grain and a fine texture. That density has a cost: Cumaru is difficult to saw and bore, glues poorly because of its natural oils, and every fastener wants a pilot hole. Left unfinished it silvers like any tropical hardwood; oiled, it holds a warm brown. It grows across Venezuela, Colombia, Brazil, Peru, Bolivia and the Guianas.
Working & finishing
Rated as difficult to saw or bore. Poor for gluing due to high density and oily nature.
Durability
Rated as very durable, resistant to brown and white-rot fungi, and has exemplary weathering characteristics.
Appearance
Reddish-brown or purplish-brown when fresh, shifting to light-brown to yellowish-brown upon exposure. Sapwood is yellowish-brown. Grain: Interlocked Texture: Fine
Applications
Cogs, flooring, decking, turnery, bearings, tool handles, railroad crossties, heavy construction.