Cumaru is hardwood from Brazil, also known as Brazilian teak. It colours warm golden brown on its own and lasts a long time outdoors. Under EN 350, Cumaru sits in class 1-2. That means it lasts on its own and can reach 25 to 40 years outdoors, even with lasting ground contact and no extra treatment. This places Cumaru among the longest lasting kinds for outdoor frames such as decking, terraces, pool decks and staging planks. Jan Sok in Meppel supplies Cumaru with an anti-slip grooved shape as part of the hardwood range.
What Cumaru is
Cumaru (Dipteryx odorata) is hardwood from South American rain forests. Trade sells it as Brazilian teak for its warm golden brown colour and teak-like look. The timber is dense, hard and wear-strong on its own. Unlike softwood, it needs no extra soak or treat to last outdoors. Cumaru is sold with a herkomst mark, so origin is legal and can be traced.
Within EN 350, Cumaru sits in class 1-2. Class 1 means it lasts a very long time (more than 25 years). Class 2 means it lasts a long time. Cumaru sits on the line of both classes, based on origin and use. For frames with lasting ground contact, Cumaru is a sound choice. It is close to Tali and just below Okan and Azobe (class 1).
Traits and class
Cumaru joins traits that make it a strong outdoor pick:
- High mass and hardness: Cumaru is much harder and heavier than Douglas. It feels solid underfoot.
- Lasts on its own: thanks to class 1-2, it resists fungi, insects and rot, with no extra soak.
- Warm golden brown colour: greys in an even way to a soft grey-brown when left with no oil.
- Lasting ground contact: unlike Douglas (class 3), Cumaru can go right in ground and water contact.
- Anti-slip grooved shape: decking planks come with a grooved face as standard. Ideal around pool decks and staging planks.
The outdoor life span of Cumaru is 25 to 40 years, based on use, weather and install. Cumaru therefore lasts much longer than treated softwood. It is also harder and richer than Douglas.
Where you use it
Cumaru is used where life span, look and safety meet:
- Decking and terraces: the classic use. Cumaru decking gives a warm wood look and lasts for decades with no swap.
- Pool decks: thanks to the anti-slip grooved face and wet hold, Cumaru is a safe, lasting choice around pools.
- Staging planks: for scaffolds and work staging with heavy load and a need for grip, Cumaru gives the needed strength and wear hold.
- Frames in ground contact: posts, beams and load parts placed right in the ground gain from the class 1-2 life span.
Cumaru is harder and richer than Douglas, but also heavier and higher in price. Those who want a lighter, lower cost deck should look at Douglas (class 3). Those who want a long life with lasting ground contact will find a strong option in Cumaru. See also Okan versus Tali decking and the decking timber review.
Pluses and drawbacks
Pluses
- Very long life span (25-40 years) with no extra treatment
- Resists fungi, insects and rot on its own
- Right for lasting ground and water contact
- Warm, rich golden brown look
- Anti-slip grooved face supplied as standard
- herkomst mark and a traced origin
Drawbacks
- Higher price than softwood and treated pine
- Heavier and harder to work than Douglas (needs heavier tools)
- Greys when left with no oil (only the look, not the build)
- Fewer sizes in stock than standard softwood
Upkeep
Cumaru is a low-upkeep timber by nature. Outdoor wood with no oil greys to a soft grey-brown. That is only the look. The build and life span stay sound. To keep the warm golden brown colour, oil the timber now and then with a hardwood oil.
Handy upkeep:
- Yearly clean with water and a soft brush
- Check screws and fixings, above all in the first year
- Optional: refresh oil once every 1-2 years to keep the colour
For lasting frames in ground contact, no further treatment is needed.
Jan Sok is based in Meppel (Celsius 10), founded in 2000 and listed under KvK 04062841. People rate the timber yard 4,8 stars from more than 141 reviews.
Common questions
Is Cumaru suitable for permanent ground contact?
Yes. With class 1-2, Cumaru resists fungi and rot on its own. It can go right in ground and water contact. Extra soak is not needed.
How long does Cumaru last outdoors?
Cumaru reaches an outdoor life span of 25 to 40 years. That depends on use, weather and install. This places it among the longest lasting kinds for outdoor frames.
Do I need to treat or oil Cumaru?
Treatment is not needed for life span. With no oil, the timber greys on its own. That is only the look and does not harm the build. To keep colour, a hardwood oil can be put on now and then.
What is the difference between Cumaru and Douglas?
Cumaru is hardwood from Brazil (class 1-2, 25-40 year life, lasting ground contact). Douglas is softwood (class 3, not for lasting ground contact, 30-50 percent cheaper). Cumaru is harder, richer and longer lasting. Douglas is lighter, cheaper and easier to work.