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 5/4x6 Cumaru Wood for Your Siding?
As exterior cladding, Cumaru siding provides a weather-tight barrier with exceptional impact resistance. The dense grain resists dents, hail damage, and woodpecker damage far better than cedar, pine, or fiber cement alternatives. Properly installed 5/4x6 Cumaru siding 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 5/4x6 profile is precision-milled to tight tolerances and available in Select and Better grade, ensuring consistent quality across your entire project. 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.
5/4x6 Cumaru Siding — Installation & Coverage Specs
- Recommended joist spacing: 16"–24" on center for 5/4x6 boards (1" actual thickness)
- Fastener placement: Secure per profile requirements, one fastener per joist minimum
- Board weight: A 12-foot 5/4x6 Cumaru board weighs approximately 31 lbs (2.60 lbs/LF)
- Coverage: Each 12-foot 5/4x6 board covers 5.5 sq ft of siding surface (5.5" face width)
- Pre-drilling required: Always pre-drill in Cumaru — the 3,330 lbf hardness prevents direct screwing
.png?width=180&quality=75&format=webp){kind=logo}