1x3 Cumaru Tongue & Groove Soffit board profile diagram
Soffit

1x3 Cumaru Tongue & Groove Soffit

This 1x3 Cumaru soffit board (Tongue & Groove profile) combines the rich grain of Cumaru (Brazilian Teak) with 3,330 Janka hardness, making it ideal for exposed eave linings and covered ceilings that endure for decades. The interlocking tongue and groove profile creates tight, seamless joints for eave linings, ceilings, and covered areas, with no visible fasteners on the finished surface. In stock and ships nationwide — order 1x3 Cumaru soffit boards online or call 1-844-674-4455 for expert guidance.

1 x 3(0.75"×2.5" actual)[19.0mm × 63.5mm]
Contractor Trusted
Expert Backed
Ships Nationwide
SKU: CUMA-1X3-TG-SB-L1

Configure Your Order

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

Durable. Stable. Aesthetic.

T&G

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:0.91 lbs/LF
1' board:0.9 lbs

1x3 Cumaru T&G Soffit — Complete Guide

Everything you need to know about t&g cumaru soffit

About 1x3 Cumaru Tongue & Groove Soffit

Cumaru lumber, particularly in a tongue-groove profile, is an ideal choice for soffit applications due to its remarkable dimensional stability and outstanding resistance to moisture exposure. This hardwood exhibits natural durability, making it well-suited for exterior overhead installations where consistent aesthetics and ventilation compatibility are required. The tongue-groove design ensures that seams fit together seamlessly, providing clean lines and enhancing the overall visual appeal of the soffit while allowing for sufficient airflow, which is essential for preventing moisture buildup in concealed spaces.

  • Dimensional stability for exterior applications
  • Exceptional durability against wear and decay
  • Tongue-groove profile enhances appearance and airflow
  • Ideal for moisture-rich environments

Key Benefits

Exceptional Durability

Cumaru's resistance to rot and insects makes it a long-lasting choice for outdoor soffits.

Low Maintenance Requirements

With natural oils providing protection, Cumaru requires minimal upkeep compared to other softer woods.

Visual Appeal

Rich colors and striking grain patterns enhance the aesthetic of any architectural style.

Technical Specifications

Janka Hardness

3330

Density

65 lbs/ft³

Durability Rating

Class 1 (very durable)

Dimensional Stability

Minimal expansion and contraction with changes in moisture content

Installation Guide

Difficulty:
Moderate

Key Tips:

  • Ensure proper ventilation gaps are accounted for in the installation
  • Use stainless steel fasteners to prevent rust
  • Leave adequate space for expansion

Recommended Tools:

Circular saw
Drill with bits appropriate for wood
Fastening screws

Maintenance & Care

Cleaning

Clean with mild soap and water as needed; avoid harsh chemicals that can damage the wood.

Finishing

Consider applying wood finish or sealant every few years to maintain appearance and protection from elements.

Weathering

Over time, Cumaru will naturally weather to a silver-gray patina if left untreated, which may reduce the need for maintenance but may alter the initial appearance.

1x3 Cumaru Tongue & Groove Soffit — Frequently Asked Questions

A 1x3 Cumaru board weighs approximately 0.91 lbs per linear foot. Cumaru has a density of about 68 lbs/ft³, making it one of the densest commercially available hardwoods. A 12-foot 1x3 Cumaru board weighs approximately 11 lbs. Always factor weight into your structural and shipping calculations.

1x3 Cumaru soffit has an expected service life of up to 50+ years when properly installed. This is 3-5× longer than pressure-treated pine and 2-3× longer than cedar. Cumaru achieves this exceptional longevity through its 3,330 Janka hardness and Class 1 durability rating, providing built-in resistance to rot, decay, insects, and fungal growth without chemical preservatives.

1x3 Cumaru soffit pricing varies by profile, grade, and board length. Select and Better grade boards typically range from $4-$12 per linear foot before shipping. While the upfront cost is higher than pressure-treated lumber, Cumaru's up to 50+-year service life makes the lifetime cost per year significantly lower. Use the configurator above for exact pricing, or request a custom quote for large orders.

Yes — 1x3 Cumaru wood soffit outperforms composite in hardness (3,330 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 wood decking costs less over its much longer lifetime. Composites do offer lower upfront maintenance, but Cumaru's natural beauty and durability make it the superior long-term investment.

Cumaru is widely considered one of the best woods for 1x3 soffit boards. With a 3,330 Janka hardness rating, Class A fire-rated certification, and up to 50+-year lifespan, Cumaru (Brazilian Teak) outperforms nearly every other commercially available wood species. Other excellent options include Cumaru (Brazilian Teak) and Massaranduba (Brazilian Redwood), but Cumaru remains the industry benchmark for premium outdoor hardwood applications.

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 1x3 Cumaru board has actual finished dimensions of 0.75" × 2.5" (19.0 x 63.5 mm). The "1x3" 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 (0.75" × 2.5") 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

1x3 Cumaru Tongue & Groove Soffit — Complete Buyer's Guide

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 1x3 Cumaru Wood for Your Soffit?

Cumaru soffit and porch ceiling boards create a warm, premium overhead aesthetic that vinyl and aluminum simply cannot replicate. The natural grain pattern adds architectural character to any covered outdoor space. Properly installed 1x3 Cumaru soffit 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 1x3 tongue & groove (T&G) profile features interlocking edges that create a seamless, flush surface with no visible gaps. Ideal for porch ceilings, soffit installations, and covered porch floors. 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.

1x3 Cumaru Soffit — Installation & Coverage Specs

  • Recommended joist spacing: 16" on center for 1x3 boards (0.75" actual thickness)
  • Fastener placement: Secure per profile requirements, one fastener per joist minimum
  • Board weight: A 12-foot 1x3 Cumaru board weighs approximately 11 lbs (0.89 lbs/LF)
  • Coverage: Each 12-foot 1x3 board covers 2.5 sq ft of soffit surface (2.5" face width)
  • Pre-drilling required: Always pre-drill in Cumaru — the 3,330 lbf hardness prevents direct screwing

Janka Hardness

3,330 lbf

Service Life

50+ years

Durability

Very Durable

Fire Rating

Class A

1x3 Cumaru Soffit — Frequently Asked Questions

1x3 Cumaru soffit has an expected service life of 50+ years when properly installed and maintained. This is 3-5x longer than pressure-treated pine and 2-3x longer than cedar. Cumaru achieves this exceptional longevity through its natural density (Janka hardness: 3,330 lbf) and Class 1 durability rating, which provide built-in resistance to rot, decay, insects, and fungal growth — all without chemical preservatives.

1x3 tongue & groove Cumaru boards interlock via a milled tongue on one edge and a corresponding groove on the other. Secure each board by blind-nailing through the tongue at a 45° angle using stainless steel ring-shank nails or by face-screwing with countersunk stainless steel screws. Always pre-drill holes in Cumaru to prevent splitting. T&G Cumaru should only be used in covered or semi-protected areas.

1x3 Cumaru soffit pricing varies by profile, grade, and board length. 1x3 Tongue & Groove boards in Select and Better grade typically range from $4-$12 per linear foot before shipping. While the upfront cost is higher than pressure-treated lumber, Cumaru's 50+ years service life makes the lifetime cost per year significantly lower. Use our online configurator above to see exact pricing for your selected options, or request a custom quote for large orders.

Related Cumaru Products & Resources

Explore more Cumaru soffit options and expert guides