4x4 Cumaru Wood Fencing board profile diagram
Fencing

4x4 Cumaru Wood Fencing

Built from Cumaru (Brazilian Teak), this 4x4 Wood fence board delivers up to 50+ years of maintenance-free privacy with 3,540 Janka hardness — no staining, sealing, or chemical treatment required. This Class B fire-rated hardwood withstands extreme weather, UV exposure, and heavy foot traffic without chemical treatment — perfect for privacy fences and property borders. In stock and ships nationwide — order Cumaru fencing online or call 1-844-674-4455 for expert guidance.

4 x 4(3.5"×3.5" actual)[88.9mm × 88.9mm]
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Ships Nationwide
SKU: CUMA-4X4-E4E-SB-L1

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Exceptional Strength and Longevity for All Outdoor Applications

Eased-Edge (Standard)
Select and Better (Standard)

This size only available in Select and Better grade

Length Guide

Available lengths: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22′

Estimated Shipping Weight
Weight per linear foot:5.95 lbs/LF
1' board:6 lbs

4x4 Cumaru Wood Fencing — Complete Guide

Everything you need to know about eased-edge cumaru fencing

About 4x4 Cumaru Wood Fencing

Cumaru lumber, known for its incredible resilience and beauty, is an ideal choice for fencing applications. Its natural properties make it suitable for a variety of environments, offering strong defenses against the elements and ground contact, ensuring your investment lasts for generations.

  • Incredibly durable and strong, with a density that ensures structural integrity.
  • Resistant to rot and insect damage, making it perfect for outdoor applications.
  • The e4e profile provides versatility and strength, widely adopted for fence construction.

Key Benefits

Exceptional Durability

With a Janka hardness rating of 3330, Cumaru is one of the hardest wood species available, making it incredibly resistant to wear and tear.

Natural Resistance

Cumaru is naturally resistant to rot, decay, and insects, ensuring a long-lasting performance even in harsh outdoor environments.

Aesthetically Pleasing

The rich, warm colors and unique grain patterns of Cumaru add visual appeal to your fencing projects, enhancing your outdoor space.

Technical Specifications

Janka Hardness

3330

Density

1,190 kg/m³ (74.4 lb/ft³)

Durability Rating

Class 1 (very durable)

Dimensional Stability

Excellent, minimal shrinkage or swelling compared to other species.

Installation Guide

Difficulty:
Moderate

Key Tips:

  • Ensure posts are securely anchored in concrete for stability.
  • Space posts no farther than 6-8 feet apart depending on the fence style.
  • Use stainless steel fasteners to prevent rusting.

Recommended Tools:

Post hole digger
Level
Screw gun or hammer (for fasteners)
Measuring tape

Maintenance & Care

Cleaning

Regularly clean with mild soap and water to maintain appearance; avoid harsh chemicals that can damage the wood.

Finishing

Apply a UV-protective oil finish annually to maintain color and prevent graying.

Weathering

Cumaru weathers beautifully, developing a silver-gray patina over time if left untreated.

Frequently Asked Questions

A 4x4 Cumaru board weighs approximately 5.95 lbs per linear foot. Cumaru has a density of about 68 lbs/ft³, making it one of the densest commercially available hardwoods. Always factor weight into your structural and shipping calculations.

Yes — Cumaru is rated Durability Class 1 (Very Durable) and is naturally resistant to rot, decay, insects, and fungal attack without chemical treatment. It is Class B fire-rated and performs exceptionally well in full exterior exposure including fencing applications. While ground contact is possible, we recommend elevating Cumaru boards at least 6" above grade for maximum lifespan.

Cumaru outperforms composite in hardness (3,540 vs ~200 Janka), lifespan (up to 50+ years vs 25-30 years), and heat resistance. Unlike composites, Cumaru won't melt, warp in extreme heat, or fade significantly. While initial cost is similar ($8-15/LF installed), Cumaru costs less over its much longer lifetime. Composites do offer lower upfront maintenance.

Cumaru requires minimal maintenance. Without treatment, it naturally weathers to an elegant silver-gray patina over 6-12 months. To maintain the original warm brown color, apply a UV-inhibiting penetrating oil (like Ipe Oil or Penofin) once or twice annually. Cleaning involves periodic washing with a mild soap solution. No sanding, staining, or sealing is required for structural durability.

Cumaru is DIY-friendly with proper preparation. Key requirements: (1) Always pre-drill all screw holes — Cumaru is too hard for direct screwing. (2) Use only 305 or 316 stainless steel fasteners — standard hardware will corrode and stain. (3) Face-screw with stainless steel trim-head screws. (4) Allow boards to acclimate on-site for 5-7 days before installation. A compound miter saw with a carbide-tipped blade is recommended.

A nominal 4x4 Cumaru board has actual finished dimensions of 3.5" × 3.5" (88.9 x 88.9 mm). The "4x4" is the nominal (rough-cut) size — after kiln drying and precision surfacing, all hardwood lumber finishes slightly smaller. This is standard across the lumber industry, similar to how a nominal 2×4 softwood measures 1.5" × 3.5". Always use the actual dimensions (3.5" × 3.5") when calculating material quantities and coverage for your project.

We responsibly, legally, and ethically source all our Cumaru. We work only with suppliers who follow responsible forestry practices with full chain-of-custody transparency. Note: We are not FSC certified. Cumaru trees grow naturally in diverse tropical forests and regenerate well under managed harvest. The extremely long lifespan (up to 50+ years) means fewer replacements compared to softwood or composite alternatives, reducing long-term environmental impact.

Shipping & Delivery

Nationwide delivery: We ship to all 50 states via LTL freight, flatbed, or terminal pickup

Typical lead time: 5-10 business days for standard orders (custom milling may add 2-3 weeks)

Shipping estimate: Final freight cost calculated at checkout based on your location and order size

Rush service available: Contact us for expedited milling and shipping options