Thermally Modified Ash Decking – A Hardwood That Ages with Grace

Lunawood’s Thermally Modified Ash decking combines the density of North American hardwood with the stability of thermal modification. The result is a premium decking material that is durable, knot-free, and designed to age gracefully in outdoor spaces. Crafted in the USA without chemicals, Lunawood’s Thermally Modified Ash brings together American craftsmanship and Finnish expertise in wood modification.

Class 1 Durability for Demanding Conditions

Through thermal modification, White Ash reaches Durability Class 1 (very durable), making it highly resistant to decay even in exposed outdoor applications. Unlike surface treatments, the process transforms the entire board, ensuring consistent durability from edge to core.

This makes Lunawood’s Thermally Modified Ash decking a dependable choice for high-use terraces, rooftop decks, and public outdoor spaces. The process is entirely chemical-free — achieved only with heat and steam — resulting in a pure, non-toxic product.

Thermally Modified Ash offers  also enhanced dimensional stability, reducing the swelling and shrinking typical of hardwoods in outdoor environments. For decking, this means boards that remain straight and true across seasons, enabling precise installations and long-lasting visual quality.

Knot-Free Surface that Weathers to Silver-Grey

Architects and designers value the completely knot-free appearance and vivid grain of Thermally Modified Ash. Its rich brown color and smooth surface bring a natural warmth and refined character to terraces, walkways, and landscaping projects.

As with all Lunawood products, when left untreated outdoors, Thermally Modified Ash decking will naturally weather into a silver-grey patina, allowing designers and builders to either embrace the soft greying process or preserve the warm tone with surface protection. Both options preserve the material’s durability against weather while keeping its premium feel.

Hidden Fixing with Konekto N

When choosing genuine wood for your project, proper installation is essential. Lunawood’s Konekto N Hidden Fixing System is designed to provide Ash decking with the longest possible service life and a premium finish. By eliminating visible screws or nails, Konekto N ensures a clean, uninterrupted surface. It also guarantees consistent spacing and sufficient air circulation, and contributes to the long-term performance of the deck for years to come.

A Sustainable Alternative to Tropical Hardwoods

Sourced from responsibly managed North American forests, Lunawood Thermally Modified Ash provides a sustainable alternative to tropical hardwood decking. Its durability, stability, and completely knot-free clarity make it a material that balances performance, sustainability, and timeless design. Lunawood’s Thermally Modified Ash decking is also available with FSC® certification.

Frequently asked questions about Thermally Modified Ash