Thermory Ash Decking

Thermory Ash decking is a White Ash, which is sourced from Northern America and European forests, and has been thermally modified. As a result, the timber has a rich chocolate brown colour throughout the full thickness of the timber, which naturally ages to a platinum grey. The original colour and tone can be preserved with UV protectant oil, or alternatively stained darker with a tinted oil.

Consumer Guide

Cost $$$$$

Low Maintenance 

High-End Look 



Ease of installation

“Thermory thermally modified timber decking is unique and beautiful in grain and colour.​”

Key Features

  • N Available in 132x20mm
  • N Will not bleed or leach
  • N Recommend 316 stainless screw fixings
  • N Great looking species
  • N Factory coating service available
  • N FSC certified is available
  • N Naturally durable hardwood – chemical free
  • N Ensure adequate ventilation around boards


Ventilation- free-air circulation under the decking is very important to help minimize cupping and warping. Proper ventilation ensures the potential difference in moisture content levels between top face and the underside of boards is reduced and extends the life and performance of the deck.

The sub deck should have at least 300mm clearance from the ground. This, in conjunction with suitable board spacing, will allow for adequate ventilation. In wet areas or over water, additional clearance is recommended. Other steps that can be taken to minimize moisture differential are – a ground level vapour barrier*(with slit drainage) and pre-coating the underside of the deck boards. Failure to provide for suitable ventilation is a major cause of early decking failure.

*Note: Using polythene sheet can create water pooling having the opposite effect.


  • Joist spacing 400-450mm recommended for 20mm thick decking.
  • Joists should be clean and sound and the screws should penetrate at least 40mm into the joists to achieve good holding.
  • Pre-drilling and counter-sinking is essential to avoid any splitting or ‘tear-out’ where the screw penetrates the Vitex.
  • Vitex hardwood decking should be spaced with 4mm min. gaps between decking boards. This will allow for some expansion & contraction as the decking boards acclimatize as well as allowing for drainage of surface water and good air circulation.

Note: These are recommendations only. An allowance for regional climatic conditions should also be factored in. Ask us for advice regarding your specific requirements!


To minimize surface checking, cupping and maintain Thermory Ash good looks we recommend coating the decking boards on all four sides with a penetrating oil prior to installation. An additional face coat following installation is also recommended. Note: When coating decking timber, ensure that the boards are free from surface marks and stains before coating. End sealing will help minimize splitting and “checking” on the ends of the boards


We strongly recommend use of stainless steel screws for fixing your decking to the deck frame. We recommend 60mm long stainless-steel screws through the pre-drilled face of a 20mm thick decking board, two screws per joist.

Maintenance Cleaning & Washing

Hardwood decks should be cleaned with a stiff brush at least once a year to clear gaps between your decking boards and remove dirt and grim. A stiff brush can also remove any surface mould which can be a slip hazard in wet weather. Keeping the deck clear of leaf litter, moving pot plants and other large objects that may hold moisture to the top of the deck, is also important for the life of the deck. Hardwood Decking can be water blasted BUT it is important to do so at a low pressure so you do not damage the fibers of the timber.

Preparation for re-coating: Removing dirt and mould prior to coating is easy with OneStopDeckShop Deck Clean, a simple 4 step system that ensures your deck is ready for re-coating. OneStopDeckShop Deck Clean active restoration agent is the recommended product for general cleaning. Follow the manufacturer’s instructions when using.

Re-coating. Always follow the manufacturer’s specification for re-coating. We can assist you with choosing the correct coating product for your job as there is a range of different products that are suited to various circumstances.

Wood Guru Pro TIPS

One Stop Deck Shop Products advocates that all hardwood decks are fixed with screws. For 132×20 decking SCREWS ARE ESSENTIAL. We recommend 60mm (for 19mm) stainless steel screws through the pre-drilled face of each board, two per joist. For 90×19 decking screws are also recommended.

0508 433 257

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