Thermally Modified Wood Vs Heat Treated wood

Understanding various wood treatment methods is crucial for selecting the right wood for architectural projects. Homeowners often choose between heat-treated and thermally modified wood to achieve both durability and aesthetic appeal. While both methods enhance wood properties, they involve distinct processes that yield different results.

In this edition of Brian’s blog, we will elaborate on these two wood processing techniques and help you choose an appropriate material for your project.

The Heat Treatment Process

Wood is exposed to high temperatures during heat treatment, which changes its physical properties. Organic acids are released from hemicellulose, breaking the cell walls’ lignin-polysaccharide bonds.

Impact of Heat Treatment

Due to exposure to extreme heat, wood’s shrinking and swelling capacity reduces by 50 to 70 percent, resulting in improved dimensional stability. Heat-treated timber also has the added advantage of increased resistance to biological threats like termites and certain microorganisms.

The adverse effects of heating wood include a gradual decrease in strength and hardness, making it easily breakable. Studies show that the reduction of hemicellulose between microfibers in the cell wall decreases tensile and bending strength by 10 to 30 percent. This makes heated wood unsuitable for constructions that demand load-bearing capabilities.

A significant change noticeable in heated wood is its change of colour. The wood material turns darker, usually more evident when processing light-coloured species like pine. The darkening effect allows manufacturers to imitate tropical species by transforming the colour of affordable, light-coloured wood materials.

Applications of Heated Wood

1. Interior Panelling & Wall Cladding
   
   • Heated wood is commonly used for stylish wall panelling for its rich, darkened colour.
   • It eliminates the need for additional stains or dyes with its warm, elegant look.
   • They do not readily attract moisture, providing stability against expansion or contraction, which is perfect for indoors.
2. Interior Doors & Partitions

   • Heated wood is ideal for interior doors and partitions, as it does not require extreme strength.
   • The warm texture and tone of the wood give the doors and partitions an aesthetic appeal.

3. Ceiling Panels
   
   • As ceilings do not require exceptional mechanical strength, heated wood can be used for panelling.
   • They make your interiors look sophisticated with a natural touch.
4.  Indoor Furniture
   
   • Light-weight furniture like cabinets, tables, chairs or shelves can be made using heated wood.
   • The wood’s slow shrinking and swelling make it suitable for indoor furniture.
   • They provide a unique, luxurious finish to the furniture.
5. Flooring
   
   • Although heat-treated wood flooring may not be as strong as solid wood, it can be used for less-frequented indoor spaces.
   • They are generally used in luxury apartments, boutique showrooms and stores focusing more on aesthetics than strength.
   • Its moisture resistance prevents warping, making it more suitable than untreated wood.

The Thermal Modification Process

Thermal modification is an advanced wood transformation method that combines high heat with steam to reconstruct wood’s fundamental components. This process improves wood’s resistance to decay, insect damage, and environmental effects, including checking, cracking, warping, or changes in size and shape.

Impact of Thermal Modification

The modification changes the wood’s composition chemically by carefully managing moisture loss. Substances altered during the process make the wood resistant to biological agents, making it durable for outdoor applications. This wood processing treatment does not require toxic chemicals to provide an added layer of protection.

The process also slows down the wood’s absorption capability, restricting movement when in contact with moisture in indoor and outdoor applications. The reduced internal stresses in thermally modified wood minimize material rejection and waste during construction.

Moreover, thermal modification increases wood’s heat and sound insulation capabilities by 30%, beyond natural wood standards. The method decreases wood’s weight and density, making it easier to handle and work with.

After being modified, the wood achieves a beautiful, deep walnut colour. This offers several eco-friendly benefits. For instance, thermally modified ash can be an alternative to tropical hardwoods.

Application of Thermally Modified Wood

1. Decking
   
   • They are moisture-resistant, ensuring the wood does not swell, shrink, or warp over time.
   • As the process does not involve using chemicals, they are environmentally friendly and safe for humans to walk bare feet.
   • Thermally modified ash, pine, and spruce look beautiful and provide a rich tone to your deck.
2. Fencing

   • They are resistant to decay, insects and moisture.
   • They do not alter shape or lose their beauty under extreme weather conditions.
   • They look elegant and provide a natural finish without needing regular maintenance.

3. Cladding & Siding

   • The weather, UV, and rot-resistant capabilities make thermally modified wood most suitable for exterior cladding.
   • They combine a modern and natural look. They can be left to develop a silver-gray patina or oiled to maintain a deeper colour.
   • It can be used in commercial and residential spaces to maintain a sleek and sustainable look.

4. Outdoor Furniture

   • Thermally modified wood’s lightweight and durable properties make it suitable for benches, tables, chairs and pergolas.
   • The moisture-resistant qualities prevent mold, rot or cracks that may develop due to humidity.
   • The rich walnut colour makes your garden, patio or park furniture look elegant.

5. Pergolas & Gazebos

   • They are modified to withstand the harsh sun, rain and extreme temperatures as seasons change without warping or cracking.
   • The moisture-resistant capabilities provide durability, which most untreated or heat-treated wood lacks.
   • Thermally modified wood’s exceptional strength and stability make it perfect for outdoor structures.

Conclusion

While heat treatment provides several advantages, its impact on wood’s mechanical properties limits its use in indoor environments. In comparison, thermal modification improves wood’s properties, making it durable indoors and outdoors.

Tropical Forest Products offers premium thermally modified wood, which combines visual appeal, sustainable usage and extended lifespan. We guarantee to provide high-quality wood materials that fulfill the strictest requirements for your design and construction projects.

Learn more about our lumber and millwork and how they can make your next project more durable and stylish.