Cumaru, also known as Brazilian Teak, is a premium tropical hardwood sourced from Amazon Basin, northern South America (Brazil, Venezuela, Guyana). With a Janka hardness rating of 3,330 lbf and a density of 65 lbs/ft³, Cumaru is classified as Class 1 - Very Durable — one of the most durable commercial lumber species available. The heartwood exhibits light to medium brown with reddish tones with interlocked grain, medium to coarse texture, creating a striking natural appearance that improves with age.
Why Choose 4x4 Cumaru Wood for Your Timbers?
Cumaru lumber is valued for its exceptional durability, natural beauty, and resistance to the elements in demanding outdoor applications. Properly installed 4x4 Cumaru timbers delivers a service life of 50+ years with minimal maintenance — an optional annual oil treatment preserves the original color, or you can let the Cumaru wood weather to a distinguished silver-gray patina. Cumaru carries a Class A - Low flame spread, making it suitable for wildfire-prone regions where code-compliant materials are required.
The 4x4 eased-edge (E4E) profile features gently rounded edges on all four sides, reducing the risk of splinters and creating a comfortable walking surface. This is the most versatile profile — suitable for face-screw installation with countersunk stainless steel fasteners. All Cumaru lumber is available in Select and Better grade with lengths ranging from 4′ to 20′. For detailed step-by-step instructions, consult our Cumaru installation guide. Long-term care recommendations are covered in our Cumaru maintenance guide.
4x4 Cumaru Timbers — Installation & Coverage Specs
- Recommended joist spacing: 24" on center for 4x4 boards (3.5" actual thickness)
- Fastener placement: Face-screw with two stainless steel screws per joist, approximately 1" from each edge of the 3.5" face
- Board weight: A 12-foot 4x4 Cumaru board weighs approximately 69 lbs (5.78 lbs/LF)
- Coverage: Each 12-foot 4x4 board covers 3.5 sq ft of timbers surface (3.5" face width)
- Pre-drilling required: Always pre-drill in Cumaru — the 3,330 lbf hardness prevents direct screwing