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What is ThermoWood Decking?

ThermoWood starts out as a standard wood species, and through various different scientific heating and steaming processes, are transformed into a thermally modified wood. In general, thermally modified wood become a more stable, and better performing version of the original wood species.  The processes also 'cook' the sugars out of the wood. This makes thermally modified wood decking, less appetizing to insects, and much more rot resistant.
Creating thermally modified wood is a sustainable process, revolutionized in Finland decades ago.  the Mataverde Thermally Modified Wood offering features beautiful real woods - recommended by many of the world's leading architects.  Thermally modified wood technology is an environmentally friendly process, requiring no chemicals or toxins.
Thermowood is a patented thermal modification process that uses only heat and water, the wood cell walls are permanently modified for the better.  This is the most effective thermal modification process for hardwood lumber species.  

Why use ThermoWood decking? 

  • STABILITY - Thermally modified decking is more stable (less wood movement, less expansion and contraction)
  • DURABILITY - Thermally modifying wood decking boards changes the wood at a cellular level. Thermally modified decking becomes more resistant to rot and less desirable to insect infestation. So they last far longer than non-modified woods of the same species.
  • LOCAL - Thermal modification transforms local North American wood species that perform as well as many tropical hardwood species.
  • SUSTAINABLE - The best thermal modification processes use only natural methods, like heat and steam, (and pressure for softwoods) creating high-performance exterior real wood products. Without adding any chemicals or toxins. 

Mataverde® Thermally Modified Wood Decking Appearance Options

What will thermally modified wood look like as it ages? Thermowood is well known for its beauty, dimensional stability and durability. But ultimately, thermally modified wood decking is still a natural wood product, and all exterior woods will age differently once they are exposed to outdoor weather conditions.


Typical Color and Graining of Mataverde ThermoWood Thermally Modified Wood Decking 


Mataverde novathermowood ash hardwood-1Mataverde ThermoWood Ash decking


The thermal modification process give the woods richer, darker brown colors. If the "new wood look" is your goal, Mataverde Thermowood decking may be finished with various sealers and maintained periodically as needed.  Oil based sealers, such as Penofin or others, work best to protect your investment.

Or, if you prefer a more natural 'weathered wood' appearance, Mataverde Thermally modified decking can be left untouched and will gradually age to a lustrous silvery gray patina over time, for a low maintenance, real wood deck.

There are appearance and maintenance options to choose from. Learn more about the appearance options and life-cycle performance of Mataverde Thermally Modified Wood. Here is the typical weathering process:


See thermally modified wood decking for yourself:


Would you like to see an actual piece of thermally modified wood decking? Order a sample today.


Thermowood aging process Initial appearance of Thermowood Ash hardwood is a chocolaty brown color

A coat of oil finish with UV inhibitors will darken the color tone to a rich dark brown color, and help protect your wood as it seasons.

As the oils weather off and the wood ages, the color will start to lighten to softer brown tones.

At this point, you may either refinish to a darker brown appearance, or

Allow the wood to 'weather out naturally' to a silvery gray patina for a low maintenance decking option


Want to learn more about the exterior wood decking weathering process?

Download the  informative, "How Woods Weather Guide" today:

Mataverde® ThermoWood Physical Characteristics and Mechanical Properties

What is thermal modification? How does the thermally modified wood process work?  The ThermoWood process produces the highest quality thermally modified wood. 

Mataverde® Thermally Modified Wood Decking has exceptional dimensional stability. ThermoWood exhibits only minor movement after it is milled and installed. An initial coating with a UV inhibiting oil finish, before installation, helps minimize any shrinkage and checking during its initial acclimation and on-site seasoning. Thermowood is an excellent decking material option to consider if you'd like a sustainable and all natural real wood deck surface for your project. 


STABILITY Thermally modified wood decking is exceptionally dimensionally stable, and exhibits very limited expansion and contraction, especially compared to other woods. An oil based finish improves the stability further and helps minimize surface checking and splitting.
DURABILITY Because the ThermoWood process 'caramelizes' the sugars in the wood, ThermoWood is exceptionally resistant to insects, fungi, decay and rot.  With normal care and maintenance, ThermoWood has a service life of 25 years or longer, depending on conditions.
HARDNESS Thermowood Ash has a Brinell hardness of 30.5 N/mm2
FIBER BENDING STRENGTH Thermowood Ash has bending strength of approximately 12,000 psi, (roughly 20% less than non-modified Ash.) 
DENSITY ThermoWood Ash has a density of approximately .62 g/cm3. It is much lighter in weight than high-density tropical hardwoods, like Ipe. Yet it is still very resistant to decay. Win/win.

Additional ThermoWood Technical Information

For more information about the Thermowood process and scientific testing:

Mataverde Thermowood Deck Installation Tips and Techniques

Mataverde thermally modified wood decking can be installed by a number of standard deck construction methods including, face screw, specified hidden fasteners and Eurotec rooftop deck system components. Because of its strength and hardness, Mataverde Thermowood decking can be installed with very similar methods to those used for other hardwood decking species.



Thermowood face screw decking installationThe most secure and best way to install Mataverde thermowood wood decking is with face screws.


  • Stainless steel screws last longer and work best.
  • Pre-Drill your screw holes for best results
  • Take care to maintain a minimum of 3/4" to 1" distance of screws from the edges and ends of boards for best results. 

Thermowood decking is harder than the original wood. The only real downside of installing thermally modified wood decking is that it is slightly more brittle than the original wood. So, this fastening method will minimize the potential for splits and will hold up very well throughout the lifetime of your Mataverde Thermowood deck. 

Download Decking Installation Guideline

Mataverde Thermowood Decking Care & Maintenance

Mataverde novathermowood decking is a low maintenance real wood decking material. As a result of thermowood technology, Mataverde Thermowood looks and acts much like other hardwood decking materials. Mataverde Thermowood is non-toxic and safe to the environment as well as humans.

Mataverde thermowood requires no maintenance beyond normal cleaning. Thermowood decking is easy to care for and there are appearance options, including oil finishes and a low maintenance option, where you can allow your deck to weather to a gray driftwood look.

 Need decking prices for a deck project? Request a Decking Quote:

Looking for the best decking options for your project?

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Need some deck design inspiration? Looking for deck ideas?

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61 pages featuring over 150 deck design ideas!