Cumaru is a tropical hardwood, also known as Brazilian teak, that naturally colours warm golden brown and is renowned for its exceptional natural durability. According to the European standard EN 350, Cumaru falls in durability class 1-2, which means it is naturally highly durable and — even with permanent ground contact — can achieve an outdoor lifespan of 25 to 40 years without chemical treatment. This places Cumaru among the most durable wood species for outdoor structures such as decking, terraces, pool decks and staging planks. Houthandel Jan Sok in Meppel supplies Cumaru with an anti-slip grooved profile as part of the hardwood range.
Definition
Cumaru (Dipteryx odorata) is a tropical hardwood species sourced from South American rainforests, marketed commercially as Brazilian teak because of its warm golden brown colour and teak-like appearance. The wood is naturally very dense, hard and wear-resistant, and — unlike softwood — requires no chemical impregnation or protective treatment to remain durable outdoors. Cumaru is sold TLV-certified, meaning its origin is legally responsible and traceable.
Within European standardisation, Cumaru is classified in durability class 1-2 (EN 350). Class 1 denotes "very durable" (>25 years lifespan), class 2 "durable". Cumaru sits at the boundary of both classes, depending on exact origin and application. For structures with permanent ground contact, Cumaru is therefore a suitable choice, comparable to Tali and just below the most durable species such as Okan and Azobe (class 1).
Properties and durability class
Cumaru combines properties that make it highly suitable for outdoor use:
- High density and hardness: Cumaru is considerably harder and heavier than Douglas. It feels solid underfoot.
- Natural durability: thanks to class 1-2, naturally resistant to fungi, insects and rot, without impregnation.
- Warm golden brown colour: greys evenly to a soft grey-brown when left untreated.
- Permanent ground contact: unlike Douglas (class 3), Cumaru can be applied directly in ground and water contact.
- Anti-slip grooved profile: decking planks are supplied as standard with a grooved profile — ideal around pool decks and staging planks.
The expected outdoor lifespan of Cumaru is 25 to 40 years, depending on application, exposure and installation. Cumaru therefore performs considerably better than impregnated softwood and is harder and more luxurious than Douglas.
Applications
Cumaru is used in practice primarily where durability, appearance and safety converge:
- Decking and terraces: the classic application. Cumaru decking offers a warm, natural appearance and lasts for decades without replacement.
- Pool decks: thanks to the anti-slip grooved profile and natural moisture resistance, Cumaru is a safe and durable choice around swimming pools.
- Staging planks: for scaffolds and work staging where heavy loading and safety are required, Cumaru delivers the necessary strength and wear resistance.
- Structures in ground contact: posts, beams and load-bearing components placed directly in the ground benefit from the natural class 1-2 durability.
Cumaru is harder and more luxurious than Douglas, but also heavier and more expensive. Those seeking a budget-friendly, lighter deck should look at Douglas (class 3). Those wanting maximum lifespan with permanent ground contact will find an excellent option in Cumaru. See also Okan vs Tali decking and the decking material comparison.
Pros and cons
Pros
- Very long lifespan (25-40 years) without chemical treatment
- Naturally resistant to fungi, insects and rot
- Suitable for permanent ground and water contact
- Warm, luxurious golden brown appearance
- Anti-slip grooved profile supplied as standard
- TLV-certified and traceable
Cons
- Higher price than softwood and impregnated pine
- Heavier and harder to work than Douglas (requires heavier tools)
- Greys when untreated (cosmetic, does not affect the structure)
- More limited availability in all dimensions than standard softwood
Maintenance
Cumaru is a low-maintenance wood by excellence. Untreated outdoor wood naturally greys to a soft grey-brown — purely cosmetic, the structure and lifespan are not affected. To preserve the warm golden brown colour, the wood can be periodically oiled with a suitable hardwood oil.
Practical maintenance:
- Annual cleaning with water and a soft brush
- Check screws and fixings, especially in the first year
- Optional: refresh oil once every 1-2 years for colour retention
For permanent structures in ground contact, no further treatment is needed.
Houthandel Jan Sok is based in Meppel (Celsius 10), founded in 2009 and registered under KvK 04062841. Customers rate the timber merchant an average of 4.8 stars based on more than 141 reviews.
Frequently asked questions
Is Cumaru suitable for permanent ground contact?
Yes. With durability class 1-2, Cumaru is naturally resistant to fungi and rot, and can be applied directly in ground and water contact. Chemical impregnation is not necessary.
How long does Cumaru last outdoors?
Cumaru achieves an outdoor lifespan of 25 to 40 years, depending on application, exposure and installation. This places it among the most durable wood species for outdoor structures.
Do I need to treat or oil Cumaru?
Treatment is not necessary for durability. Untreated, the wood naturally greys, which is cosmetic and does not affect the structure. To retain colour, a hardwood oil can be applied periodically.
What is the difference between Cumaru and Douglas?
Cumaru is tropical hardwood (class 1-2, 25-40 year lifespan, permanent ground contact); Douglas is softwood (class 3, not for permanent ground contact, 30-50% cheaper). Cumaru is harder, more luxurious and more durable; Douglas is lighter, cheaper and easier to work.