Benchmark Thermo-Ash deck


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Thermory Benchmark of thermally modified ash is undoubtedly one of the best-looking decks. But even more important properties are concealed under the surface – durability and easy installation. All of these qualities are found at a high level in thermally modified ash decking.

Our thermally modified ash has the highest durability class, it doesn’t contract or expend, it’s free of knots and has a deep, rich tone. The assortment includes profiles that let you install the deck without visible joints and using the world’s easiest method. Unlike tropical wood, ash won’t ruin your tools and the dust isn’t toxic. Thermally modified wood is natural, chemical-free and environmentally safe.

Highest durability class, knotless and comfortable for your feet

Aesthetically pure and
beautiful result

Splinter-free deck

The wood becomes more durable and its moisture content decreases

Highest durability class

Does not become as hot in the sun

Wood from sustainable forests with chemical-free modification

Our Benchmark Ash is architects and designers favourite. See the references in gallery.

Why choose Benchmark Thermo-Ash decking?

  • If you are looking for a durable and stable material suitable for outdoor use, Thermory Benchmark Thermo-Ash is the right choice for you. This is the ideal choice for those who care about the environment and wish to reduce their ecological footprint.
  • Thermally modified ash is an environmentally friendly alternative to tropical wood – our wood comes from sustainably managed forests; we never purchase timber originating from endangered forests, tropical forests or rainforests.
  • Thermally modified ash has biological durability characteristic to tropical (class 1, 25+ years) and better dimensional stability.
  • Thermally modified wood has lower moisture absorption capability and rate and less moisture-induced wood deformation as a result, meaning that the wood shrinks and expands less when used outdoors.
  • Our thermally modified ash is a nature-friendly material as no chemicals are used for thermal modification and no waste is generated in the course of the process.
  • Thermo-Ash is easier to process compared with tropical timber.


Additional options for flawless finish and easy installation

Highlights the wood’s
natural grain

Flawless finish,
no visible screws

Reduces waste,
saves expenses

Innovative and simple
fixing methods

Standard selection of Benchmark Thermo-Ash products:


Our standard products offer more flexible purchase volumes and shorter delivery times. The rest of our products are made to order.
Request additional information on minimum quantities and delivery terms.

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Thermally modified ash is a responsible alternative to tropical timber

Tropical timber is considered the standard of durable wood. This wood is of course valuable, but millions of hectares of rainforests are cut down to acquire it. Our alternative to this is to use tree species that, after thermal modification, offer wood of comparable durability and functionality to that of tropical tree species, without destroying the rainforests.

Our Thermo-Ash decking has natural durability equal or better than that of tropical wood and a rich deep colour. Unlike tropical hardwood, Thermo-Ash is environmentally friendly, non-toxic and rot-resistant for at least 25 years if installed properly.


Ash is lightweight and durable

Ash (Fraxinus excelsior or Fraxinus americana) is a deciduous tree of the Oleacae family that grows in Europe and North America. Ash wood is valuable, durable and strong. With its decorative look and attractive texture, this wood beautifully complements your walls and floor surfaces. Thermal modification adds exceptional durability and an exotic tone to ash wood, making it an environmentally friendly alternative to tropical deciduous trees.

  • Decking
  • Cladding
  • Modular solutions

The colour of the wood will change over the course of time

Thermal modification makes the colour of ash wood an exotic deep brown. A brushed finish will further highlight the depth and pattern of the wood.

As with any other wood, the surface of thermally modified ash will acquire a natural silver grey colour over time. This process starts immediately after the products are installed and can take a few months to several years depending on how much UV light they are exposed to. The durability of the boards is not affected.

If you would like to preserve the tone of thermally modified wood, we recommend oiling the boards once a year using a UV-resistant oil.

Thermory Benchmark Thermo-Ash

Deck maintenance. To oil or not to oil?

Thermally modified decking boards do not necessarily require surface treatment, but regular maintenance and oiling will refresh the appearance of your deck and make it easier to clean.

  • We recommend cleaning and maintaining the deck before the start of the summer season.
  • Lightly sanding faded boards will remove the silvery surface colour and restore the wood’s original appearance.
  • If you would like to preserve or change the tone of thermally modified wood, apply UV-resistant oil to the boards once a year.
  • If you would like to preserve the tone of boards that have turned grey over time, use colourless oil without a UV filter on the boards.
  • The oil should be applied only to clean, level, dust-free surfaces.


Five recommendations for installing decking made of Benchmark Thermo-Ash

The right installation techniques are extremely important to ensure the most beautiful and truly long-lasting Thermory decking.

  • We recommend using Thermory Ash or Thermory Spruce (both durability class 1) underconstruction. This ensures that your underconstruction lasts at least as long as your decking.
  • Choose the PaCS Strip, T-4, T-6 or TENI clip fixing to achieve a deck surface without screw holes and visible screws.
  • If you decide to use screws for fixing the decking, we recommend pre-drilling the screw-holes in the boards to avoid splitting the wood with screws. The diameter of the drill bit must be 1 mm bigger than the screw diameter.
  • By choosing decking boards with end-matching you can install boards of different lengths with the least possible time, material costs and labour input. Thermory end-matching is tested for load bearing and do not have to be laid on the underconstruction
  • Apply end wax to all ends of the decking boards before installation to ensure longer service life.