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Cumaru Decking



With decades of proven performance in high profile commercial applications, Iron Woods Cumaru is renowned for its natural resistance to everything nature can throw at it. A South American species recognized for its incredible strength and durability, Cumaru can be used in ground contact without preservatives. It’s widely used in commercial applications, such as boardwalk and bridge decking, where large volumes of fixed dimensions and lengths are required.

Premium Grade
100% clear all heartwood and graded for appearance on the face, back, and edges. Unsound milling defects not allowed.

Availability
Product availability rough sawn full or nominal dimensions S4S or S4S E4E. See full availability details.




FEATURES & BENEFITS

Why Choose Cumaru?


NATURALLY DURABLE

Kiln dried and pre-stabilized to the same high standards we apply to all our decking products.

Low Maintenance

Cumaru naturally weathers to light silvery gray tones—no need to apply annual sealers. Regular cleaning and refinishing with exotic hardwood oil can maintain or restore its natural color

Boardwalk Best

Cumaru is the species of choice for the boardwalk industry and commercial projects where heavy dimensions and large volumes of single lengths or FSC certification is required.

Timeless Beauty

Weather naturally to an attractive silver gray or maintain the natural golden yellow to reddish brown color by cleaning and refinishing. Or both. Your choice.

Stands Up to the Elements

Iron Woods® Cumaru Decking stands up to the elements year-round – from heat and humidity to salt water spray and brutal winters.

Premium Grade

100% heartwood. 100% clear. No unsightly knots or sapwood streaks. Grading on all faces and edges allows for any face selection you choose.

NATURALLY DURABLE

Kiln dried and pre-stabilized to the same high standards we apply to all our decking products.

Low Maintenance

Cumaru naturally weathers to light silvery gray tones—no need to apply annual sealers. Regular cleaning and refinishing with exotic hardwood oil can maintain or restore its natural color

Boardwalk Best

Cumaru is the species of choice for the boardwalk industry and commercial projects where heavy dimensions and large volumes of single lengths or FSC certification is required.

Timeless Beauty

Weather naturally to an attractive silver gray or maintain the natural golden yellow to reddish brown color by cleaning and refinishing. Or both. Your choice.

Stands Up to the Elements

Iron Woods® Cumaru Decking stands up to the elements year-round – from heat and humidity to salt water spray and brutal winters.

Premium Grade

100% heartwood. 100% clear. No unsightly knots or sapwood streaks. Grading on all faces and edges allows for any face selection you choose.



FEATURES & BENEFITS

Why Choose Cumaru?


NATURALLY DURABLE

Kiln dried and pre-stabilized to the same high standards we apply to all our decking products.

Low Maintenance

Cumaru naturally weathers to light silvery gray tones—no need to apply annual sealers. Regular cleaning and refinishing with exotic hardwood oil can maintain or restore its natural color

Boardwalk Best

Cumaru is the species of choice for the boardwalk industry and commercial projects where heavy dimensions and large volumes of single lengths or FSC certification is required.

Timeless Beauty

Weather naturally to an attractive silver gray or maintain the natural golden yellow to reddish brown color by cleaning and refinishing. Or both. Your choice.

Stands Up to the Elements

Iron Woods® Cumaru Decking stands up to the elements year-round – from heat and humidity to salt water spray and brutal winters.

Premium Grade

100% heartwood. 100% clear. No unsightly knots or sapwood streaks. Grading on all faces and edges allows for any face selection you choose.

NATURALLY DURABLE

Kiln dried and pre-stabilized to the same high standards we apply to all our decking products.

Low Maintenance

Cumaru naturally weathers to light silvery gray tones—no need to apply annual sealers. Regular cleaning and refinishing with exotic hardwood oil can maintain or restore its natural color

Boardwalk Best

Cumaru is the species of choice for the boardwalk industry and commercial projects where heavy dimensions and large volumes of single lengths or FSC certification is required.

Timeless Beauty

Weather naturally to an attractive silver gray or maintain the natural golden yellow to reddish brown color by cleaning and refinishing. Or both. Your choice.

Stands Up to the Elements

Iron Woods® Cumaru Decking stands up to the elements year-round – from heat and humidity to salt water spray and brutal winters.

Premium Grade

100% heartwood. 100% clear. No unsightly knots or sapwood streaks. Grading on all faces and edges allows for any face selection you choose.



Time tested for decades of performance.



Your next project begins with Iron Woods. Let’s get started.

Tell us what you’re looking for.


Your next project begins
with Iron Woods.



Technical Details


Our technical support is unmatched in the industry. Have a question? We’re here to help. Always.


Storage & HandlingSpans & SpacingDeck VentilationFinishingBest Practices
Storage & Handling
  • Iron Woods® Cumaru decking is supplied as kiln-dried lumber and is for outdoor use only.
  • Store the wood out of direct sunlight and be sure to keep it dry and off the ground.
  • Allow the wood to acclimate and stabilize to the installation area’s humidity before installing.
  • Cumaru will naturally slightly darken on exposure.

Spans & Spacing

These spans are designed for Cumaru to allow for minimal deflection of the deck surface. Contact us for maximum spans and engineering data.

 Load Size
Board Size100 psf
1×416″
1×616″
5/4×624″
  • Allow a 3/16″ gap between 6″ wide deck boards and a 1/8″ gap between 4″ wide deck boards for drainage, airflow and expansion. 
  • Kiln dried decking may expand 1/8″ on 6″ wide boards during times of high moisture. 
  • Expect some shrinkage in width in hot or dry areas.

Deck Ventilation
  • Adequate ventilation of the deck is essential for long-term stability and to minimize cupping. 
  • Proper air ventilation allows air to flow in from outside the deck area, under the joists and up through the gaps between the deck boards.

Finishing
  • Seal immediately after installation to reduce the potential for surface checking. If installing over a prolonged period or during hot weather, sealing after each phase is recommended. 
  • Be sure to seal all ends immediately after cutting with Anchorseal clear wax end sealer (available from your Iron Woods® dealer) in order to reduce end checking.
  • To maintain a golden brown color, use a transparent, penetrating oil-based sealer with UV inhibitors in a trans-oxide-pigment tint and reapply annually, or as needed.
  • If you prefer a natural, silvery-gray appearance, use a clear oil-based sealer for the first coat and then simply let the wood weather to its natural gray color. 
  • If you want to return silver-gray wood to the original color, use a “wood brightener.” Careful power washing and/or sanding can help to remove the grayed wood.
  • “First Coat” Iron Woods® may be available by special order. These orders come pre-finished with “First Coat” for those customers desiring to take the guesswork out of their first application of wood sealant.

Best Practices
  • Download a more in-depth, printer-friendly PDF Best Practices Guide
  • Click the link to open/download the PDF in most browsers. You can also right-click and choose to Save Link As.


Technical Details


Our technical support is unmatched in the industry. Have a question? We’re here to help. Always.


Storage & HandlingSpans & SpacingDeck VentilationFinishingBest Practices
Storage & Handling
  • Iron Woods® Cumaru decking is supplied as kiln-dried lumber and is for outdoor use only.
  • Store the wood out of direct sunlight and be sure to keep it dry and off the ground.
  • Allow the wood to acclimate and stabilize to the installation area’s humidity before installing.
  • Cumaru will naturally slightly darken on exposure.
Spans & Spacing

These spans are designed for Cumaru to allow for minimal deflection of the deck surface. Contact us for maximum spans and engineering data.

 Load Size
Board Size100 psf
1×416″
1×616″
5/4×624″
  • Allow a 3/16″ gap between 6″ wide deck boards and a 1/8″ gap between 4″ wide deck boards for drainage, airflow and expansion. 
  • Kiln dried decking may expand 1/8″ on 6″ wide boards during times of high moisture. 
  • Expect some shrinkage in width in hot or dry areas.
Deck Ventilation
  • Adequate ventilation of the deck is essential for long-term stability and to minimize cupping. 
  • Proper air ventilation allows air to flow in from outside the deck area, under the joists and up through the gaps between the deck boards.
Finishing
  • Seal immediately after installation to reduce the potential for surface checking. If installing over a prolonged period or during hot weather, sealing after each phase is recommended. 
  • Be sure to seal all ends immediately after cutting with Anchorseal clear wax end sealer (available from your Iron Woods® dealer) in order to reduce end checking.
  • To maintain a golden brown color, use a transparent, penetrating oil-based sealer with UV inhibitors in a trans-oxide-pigment tint and reapply annually, or as needed.
  • If you prefer a natural, silvery-gray appearance, use a clear oil-based sealer for the first coat and then simply let the wood weather to its natural gray color. 
  • If you want to return silver-gray wood to the original color, use a “wood brightener.” Careful power washing and/or sanding can help to remove the grayed wood.
  • “First Coat” Iron Woods® may be available by special order. These orders come pre-finished with “First Coat” for those customers desiring to take the guesswork out of their first application of wood sealant.
Best Practices
  • Download a more in-depth, printer-friendly PDF Best Practices Guide
  • Click the link to open/download the PDF in most browsers. You can also right-click and choose to Save Link As.


Need to Know

Product Availability



NOMINAL SIZELENGTHSLENGTHS
1" X 6" – 5"/4" X 6"KD Decking8'-20'
2" x 4" – 2" x 6"AD Dimensional Lumber8'-20'
3" x 6" – 3" X 12"AD Timbers8'-20'
4" x 4" – 4" x 12"AD Timbers8'-20'
6" x 6" – 6" x 12"AD Timbers8'-20'
8" x 8" – 8" x 12"AD Timbers8'-20'
10" x 10" – 10" x 12"AD Timbers8'-20'
12” x 12”AD Timbers8'-20'




PRODUCT COMPARISON


Which wood is right for you?



 
Type
Maintenance
Decay Resistance
Termite Resistance
Strength
Movement in Service
Fire Rating Class
Weight per cu. ft.
Bending Strength (in psi)
E-modulus
Shear Strength
Hardness




BETTER TOGETHER


Fastening Systems

We make fastening easy. Iron Woods decking can be installed using the EB-TY Hidden Deck Fastening System, the Starborn Color Matched Pro-Plug System, or Iron Woods Boardwalk and Deck Screws.







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Your next project begins with Iron Woods. Let’s get started.

Tell us what you’re looking for.



Your next project begins with Iron Woods. Let’s get started.

Tell us what you’re looking for.