What Is Thermally Modified Wood Decking? 

Thermally modified wood decking is created through a specialised heat-treatment process that enhances the wood’s performance without using chemicals. The timber is heated in a controlled, oxygen-free environment, altering its internal structure. This transformation reduces water absorption and greatly improves stability, resulting in decking that resists rot, decay, and warping, all while maintaining a rich colour that runs through the entire board. 

Why Demand Is Rising 

Thermally modified decking is rapidly becoming the preferred choice for modern outdoor design. Here’s why: 

• Sustainability: No chemicals, just heat. A natural alternative to pressure-treated or composite boards. 
• Durability: Even softwoods become tougher and more dimensionally stable for long-term outdoor use. 
• Low Maintenance: Less swelling, cracking, or surface degradation, even through changing weather conditions. Especially species like our Thermo-Ash which come pre-oiled with UV protection. 
• Aesthetic Appeal: The process produces deeper, richer tones and a premium finish that weathers elegantly. 

It’s no surprise that interest in this material is rising fast across the UK. 

Thermo Ash: Premium Performance, Naturally 

Our Thermo Ash decking combines natural elegance with remarkable resilience. Featuring deep chocolate-brown tones, exceptional stability, and a refined smooth finish, it’s a premium hardwood choice that excels in the UK’s climate. Thermo Ash is ideal for projects where both style and longevity matter, whether you choose hidden fixings for a seamless look or a traditional screw-through installation for a classic finish. 

Introducing Thermowood Pine Decking – Now Available 

To meet growing demand and complement our existing thermally modified range, we’re excited to announce that Thermowood Pine decking is now available to order at Southgate Timber. 

This new addition to our range features: 

• Profile: 25 x 140mm Smooth Decking 
• Fixing Options: Compatible with both hidden fix and face-screw systems 
• Key Benefits: Lightweight, durable, and cost-effective, ideal for contemporary outdoor builds 

We already supply Thermowood Pine cladding and fencing, making this new decking the perfect match for cohesive projects. You can now source cladding, fencing, and decking all from the same material, ensuring consistent tone, grain, and performance throughout. Thermowood Pine provides a practical balance between sustainability, durability, and affordability, extending the design possibilities of our thermally modified range. 

As the outdoor living trend continues to grow, thermally modified timber is setting new standards for performance and sustainability. At Southgate Timber, we’re proud to build on the success of our thermally modified materials by expanding our decking range. 

With Thermo-Ash and Thermowood Pine decking now available, perfectly complementing our existing Thermowood cladding and fencing, we’re investing in a future where natural timber remains the benchmark for beauty, longevity, and environmental responsibility.