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1x2 Cumaru Tongue & Groove Siding board profile diagram
Siding

1x2 Cumaru Tongue & Groove Siding

This 1x2 Cumaru Tongue & Groove siding board offers unmatched exterior cladding longevity, backed by Cumaru's 3,540 Janka hardness and a natural lifespan of up to 50+ years. The interlocking tongue and groove profile creates tight, seamless joints for exterior cladding and accent walls, with no visible fasteners on the finished surface. In stock and ships nationwide — order Cumaru siding online or call 1-844-674-4455 for expert guidance.

1 x 2(0.75"×1.5" actual)[19.0mm × 38.1mm]
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Ships Nationwide
SKU: CUMA-1X2-TG-SB-L1

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

1x2 Tongue-Groove Profile for Superior Siding and Cladding

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:0.55 lbs/LF
1' board:0.6 lbs

1x2 Cumaru Tongue & Groove Siding — Complete Guide

Everything you need to know about t&g cumaru siding

About 1x2 Cumaru Tongue & Groove Siding

Cumaru lumber is increasingly recognized as an ideal material for exterior siding and cladding due to its exceptional durability and aesthetic value. Its dimensional stability ensures it retains its shape and integrity, even in fluctuating weather conditions, while its natural resistance to elements makes it a practical choice for various climates. The tongue-groove profile not only enhances the installation process but also contributes to the visual impact of the finished product, creating clean shadow lines that elevate exterior designs. The orientation options further allow for creative expression in architectural applications.

  • High dimensional stability for long-lasting performance
  • Natural weather resistance against moisture and UV rays
  • Aesthetic appeal with tongue-groove profile creating beautiful shadow lines
  • Versatile application in both vertical and horizontal installations

Key Benefits

Exceptional Durability

Cumaru is recognized for its resilience against rot and insect attacks, making it ideal for exterior use.

Visual Appeal

The tongue-groove design not only allows for a seamless fit but also creates enhanced shadow lines that add depth to building exteriors.

Longevity

With proper maintenance, Cumaru siding can last for decades, providing excellent value over time.

Dimensional Stability

Tightly fitting tongue-and-groove profiles help control movement and distortion, maintaining a pristine appearance after installation.

Technical Specifications

Janka Hardness

3330

Density

65 lbs/ft³

Durability Rating

Very Durable

Dimensional Stability

Excellent

Installation Guide

Difficulty:
Moderate

Key Tips:

  • Ensure proper ventilation behind cladding
  • Leave space for expansion and contraction
  • Use appropriate fasteners that complement the tongue-and-groove profile

Recommended Tools:

Circular saw
Cordless drill
Level
Measuring tape

Maintenance & Care

Cleaning

Regularly clean with a mild soapy water solution and rinse thoroughly to maintain the wood’s appearance.

Finishing

Apply a UV-protective finish annually to prevent graying and enhance color retention.

Weathering

Cumaru naturally weathers to a silvery-gray if left untreated, but regular oiling will maintain its rich color.

Frequently Asked Questions

A 1x2 Cumaru board weighs approximately 0.55 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 siding 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 1x2 Cumaru board has actual finished dimensions of 0.75" × 1.5" (19.0 x 38.1 mm). The "1x2" 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" × 1.5") 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.

Related Guides & Resources

Understanding Tongue-and-Groove Profiles for Exterior UseBest Practices for Siding InstallationMaintenance Tips for Wooden Cladding

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

1 x 2 Cumaru Tongue & Groove Siding — 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.

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 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 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 1 x 2 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.

Janka Hardness

3,330 lbf

Service Life

50+ years

Durability

Very Durable

Fire Rating

Class A

1 x 2 Cumaru Siding — Frequently Asked Questions

Cumaru siding 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.

1 x 2 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.

Cumaru siding pricing varies by size, profile, grade, and board length. 1 x 2 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.

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