1x2 Cumaru Tongue & Groove Soffit board profile diagram
Soffit

1x2 Cumaru Tongue & Groove Soffit

This 1x2 Cumaru Tongue & Groove soffit board combines the rich grain of Cumaru (Brazilian Teak) with 3,540 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 Cumaru soffit 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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Durable, Stable, and Aesthetically Pleasing Soffit Solution

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:0.55 lbs

1x2 Cumaru Tongue & Groove Soffit — Complete Guide

Everything you need to know about t&g cumaru soffit

About 1x2 Cumaru Tongue & Groove Soffit

Cumaru lumber is an ideal choice for soffit applications due to its exceptional dimensional stability, durability, and inherent resistance to moisture. The tongue & groove profile not only ensures clean lines and an elegant finish but also promotes compatibility with ventilation solutions, reducing the potential for moisture buildup. This results in a long-term, visually appealing installation that maintains structural integrity even under challenging weather conditions.

  • Exceptional resistance to moisture exposure
  • Dimensional stability ensures longevity
  • Tongue & groove profile allows for seamless installation and clean aesthetics
  • Perfect for ventilated or non-ventilated soffit designs

Key Benefits

Outstanding Durability

Cumaru is known for its toughness and resistance to wear, making it suitable for high-exposure applications such as soffits.

Moisture Resistance

Its natural oils make Cumaru highly resistant to moisture, preventing rot and fungal growth.

Low Maintenance

Requires minimal upkeep, saving time and costs over its lifespan while maintaining its beauty.

Aesthetic Versatility

The rich color variations and distinct grain patterns enhance the visual appeal of any architectural design.

Technical Specifications

Janka Hardness

3330

Density

8.5 lbs/ft³

Durability Rating

Class A for decay resistance

Dimensional Stability

Highly stable with minimal expansion/contraction

Installation Guide

Difficulty:
Moderate

Key Tips:

  • Ensure proper ventilation to prevent moisture accumulation
  • Space expansion gaps to accommodate humidity changes
  • Use stainless steel or coated fasteners to prevent corrosion

Recommended Tools:

Circular saw
Drill/driver
Measuring tape
Square
Level

Maintenance & Care

Cleaning

For cleaning, simply use a mild soap solution and rinse with water. Avoid harsh chemicals that can affect the wood finish.

Finishing

Consider applying a penetrating oil or clear sealant annually to maintain the wood's natural beauty and protect against sun damage.

Weathering

Cumaru will weather to a silver-grey patina over time if left untreated, which may be desirable for certain aesthetics.

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 soffit 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.

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