5/4x4 Cumaru Wood Outdoor Flooring board profile diagram
Outdoor Flooring

5/4x4 Cumaru Wood Outdoor Flooring

Engineered for covered porches and protected outdoor spaces, this 5/4x4 Cumaru Wood flooring board leverages Cumaru's 3,540 Janka hardness for a natural lifespan of up to 50+ years. This Class B fire-rated hardwood withstands extreme weather, UV exposure, and heavy foot traffic without chemical treatment — perfect for covered porches and outdoor living spaces. In stock and ships nationwide — order Cumaru outdoor flooring online or call 1-844-674-4455 for expert guidance.

5/4 x 4(1"×3.5" actual)[25.4mm × 88.9mm]
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SKU: CUMA-54X4-E4E-SB-L1

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Select profile, grade, and length below to see live pricing

Perfect for Patios, Balconies, and More

Eased-Edge (Standard)

Select and Better is our standard 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:1.70 lbs/LF
1' board:2 lbs

5/4x4 Cumaru Wood Outdoor Flooring — Complete Guide

Everything you need to know about eased-edge cumaru outdoor flooring

About 5/4x4 Cumaru Wood Outdoor Flooring

Cumaru lumber, particularly in the E4E profile and 5/4x4 nominal (1x3.5 actual) size, is an exceptional choice for outdoor flooring applications. Known for its superior durability and aesthetic appeal, Cumaru performs remarkably well under various weather conditions, and its slip-resistant surface makes it safe for outdoor use. The E4E profile not only enhances the visual appeal with a clean finish but also eases installation, allowing for a seamless and attractive outdoor space.

  • Highly durable and resistant to wear
  • Slip-resistant surface for safety
  • Resistant to moisture and insect damage
  • Aesthetic appeal with varied grain patterns

Key Benefits

Exceptional Durability

Cumaru lumber exhibits outstanding resistance to wear, making it ideal for high-traffic outdoor areas.

Moisture and Insect Resistance

This wood species naturally resists decay and insects, extending its lifespan in outdoor settings.

Aesthetic Variety

Cumaru features a rich color palette and distinct grain patterns, providing a unique look for any outdoor project.

Technical Specifications

Janka Hardness

3330

Density

800 kg/m³ (approx)

Durability Rating

Class 1 (Highest Durability)

Dimensional Stability

Excellent, with limited movement after installation

Installation Guide

Difficulty:
Moderate

Key Tips:

  • Ensure proper substructure for support
  • Leave appropriate spacing for ventilation and expansion
  • Use stainless steel fasteners to prevent corrosion

Recommended Tools:

Drill
Saw (for cutting to size)
Tape measure
Level

Maintenance & Care

Cleaning

Regularly sweep to remove debris; clean with mild soap and warm water when necessary.

Finishing

Apply a UV protective oil periodically to maintain color and prevent weathering.

Weathering

While naturally resistant to weather, periodic maintenance will enhance appearance and longevity.

Frequently Asked Questions

A 5/4x4 Cumaru board weighs approximately 1.70 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 outdoor flooring 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 5/4x4 Cumaru board has actual finished dimensions of 1" × 3.5" (25.4 x 88.9 mm). The "5/4x4" 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 (1" × 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