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 1x1 Cumaru Wood for Your Railing?
Cumaru railing components match your hardwood deck perfectly and provide a warm-to-the-touch graspable surface that aluminum and cable rail systems cannot offer. Properly installed 1x1 Cumaru railing 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 1x1 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.
1x1 Cumaru Railing — Installation & Coverage Specs
- Recommended joist spacing: 16" on center for 1x1 boards (0.75" actual thickness)
- Fastener placement: Face-screw with two stainless steel screws per joist, approximately 1" from each edge of the 0.75" face
- Board weight: A 12-foot 1x1 Cumaru board weighs approximately 3 lbs (0.27 lbs/LF)
- Coverage: Each 12-foot 1x1 board covers 0.8 sq ft of railing surface (0.75" face width)
- Pre-drilling required: Always pre-drill in Cumaru — the 3,330 lbf hardness prevents direct screwing