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 Ash Decking

The Best Decking Solution on the Modern Market

Thermo-treated Decking

ThermA Decking

Thermally-modified decking is one of the main applications of thermo-treated wood.  Developed in Finland in 1990-th as a Green alternative for pressure-treated pine decks, thermo modification is now the main way to protect the wood for outdoors in Europe.  In the European Union, chemical additives usage in wood protection was prohibited in 2004. In the USA and Canada, no chemical wood protection additives are allowed in such sectors as children's playground production, decks for waterfront homes, and pallets for transportation of foods since 2005.

The cost of ownership of beautiful factory oiled Thermo-treated Ash decking, over time, will be 2-3 times less than the cost of cheapest pressure-treated (PT) Pine decking of lowest grade. Please consider this:


- PT Pine decks: $2/SF + $2.5/SF oiling after installation = $4.5/SF,

2 Years:

- PT Pine needs oiling every year (+$2.5/SF X 2) = $9.5/SF

5 Years:

- PT Pine usually needs replacement (+ $2/SF boards + $2/SF installation + $2.5/SF X 4 oiling) = (since initial purchase)

$2 + $2.5 + $2.5 + $2.5 + $2.5 +$2 + $5/SF + $2.5 = $19/SF

Thermo-treated Decking
Compare costs of Deck's Ownership

Years of ownership





Pressure-treated Pine, contractor oiled, $/SF









 Decking Gallery

 Decking Gallery

Advantages of Thermo-Treated Decking

  • Real Wood: Thermally modified Ash and decking are the most beautiful real hardwood decks for any residential and commercial application.

  • 100% Green: Made from thermally treated wood for indoors and outdoors. No chemicals were added.

  • Low Maintenance Products: Due to increased dimensional stability the thermally modified decks require longer maintenance intervals compared to the other wood decking products. 


  Additional advantages:

  • Lighter weight due to thermo modification and reduced moisture 

  • Shipped 4-sides factory oiled with UV-protection

  • Reduced combustibility (Class B fire rating)

  • Improved resistance to termites

  • Janka Hardness – 1300 Lbf for and Ash, 850 Lbf for SYP

  • Made in the USA from American Ash, and Pine

  • 25-year warranty against decay

Green thermo-trated wood

Four-Sides Factory Oiling Advantages:

  • Makes product ready to use

  • Prevents fading of color under sunlight

  • Prevents seasonal surface checking

  • Makes wood grain sound and attractive

  • Our included in price FOUR sides oiling saves you $2-4/SF which contractors usually charge for ONE-side surface oiling on site; oiling of the backside is extremely important to increase the lifetime of the products

We made our thermo-treated wood decking in the USA

Compare Thermo-Treated Decking to the other deckings

Versus pressure-treated decks: Thermo-treated Decking is a 100% Green product, that doesn’t crack, shrink and swell as pressure-treated lumber.
Versus composite: Thermo-treated Decking is not overheating under sunlight and it is real wood.
Versus exotic woods: Thermo-treated Ash Decking is much lighter in weight, easier to work with, more stable in size and better in appearance.

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Difference between Thermo-Treatred Oak and Ash

- Oak is "open grain wood", Ash is "close grain" wood. 

- Ash is 1,320 Lbf Janka Hardness, Oak is 1,290.

- Both species have similar grain structures and similar appearance. 


Thermo-treated wood like any organic material is fading under sunlight. Both species are fading about the same way and shade. Factory oiling prevents fading for the first 1-2 years (depending on the intensity of sunlight) and to maintain the original color requires oiling every 1-2 years. Oiling also prevents seasonal surface checking. If wood faded it's easy to restore the original color just by lightly sanding the surface of the decks. Small seasonal checks (which are opening and closing depending on ambient moisture in the air) do not affect the product properties. 


The thermal modification protects the wood against decay for at least 25 years.  Nevertheless, the original appearance of the product depends on timely maintenance and usage as directed. 

Samples Availability

- Samples of 12 in. long available for all species 

- Flyers added to each order of samples

Decking Market and Prices

A general idea of Thermally-Modified oiled decking is:


Thermo-treated Oak or Ash decking is a great real wood alternative for somebody who considers buying Composite decks or Tropical woods - we offer beautiful real wood hardwood floors outdoors, oiled on four sides, not overheating under the sun and completely Green - for the same (or even less) price.

In the low-end price segment is a low-quality chemically-treated Pine (# 2 Com Grade) at the price level of $1/LF. It's the most usable product in the US regardless of all disadvantages (harmful chemicals, low-quality lumber, twisted and cracked boards even on the store's shelves). The other low-price option is a low-end composite (starting from $1.5/LF), which is hollow inside and easy to crack. We do not consider these products to compare to our thermo-treated wood products as we initially use Clear Grade woods for our products.

In the low-medium price segment is KDAT (Kiln Dries After Pressure-Treatment) Pine (usually of # 1 Com Grade) - about $2.5 - $3/LF, medium quality composite $3 - $4/LF, Cedar and Red Wood. Our thermally modified Pine decks compete with these products offering much greater value for the same price. 


In the high-medium price segment is a good quality composite ($4.5-6/LF) and some exotic woods like Ipe. Our thermally modified  Ash decking are even at the low end of this price segment offering a much better product for the same price. 

In the high-end price segment are: PVC plastic decking ($6 - $10/LF), high-end lines of composite ($6 - $8/LF), some Thermowood brands of thermally modified Ash (Thermory), and exotics like Teak or Black Wood (up to $15/LF). Our thermally modified  Ash decking products offer even greater value at much lower prices. We are also the only one on the market to offer 4-sides factory oiling for our thermally modifies decking and siding products. 


ThermA Decking Flyer
Installation Instructions
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