Thermowood is a modification process involving steam and high heat treatment. This process is used to change the physical and chemical properties of wood, increasing its durability and improving its color. The process usually takes between 48 and 96 hours depending on the species, width, and initial moisture content of the wood. The process is divided into three stages - high temperature drying, heat treatment, and cooling. During the high temperature drying, substances such as glucose, citric acid, and resin that can reduce the lifespan of the wood are resolved and crystallized. This process results in improved physical properties while also making the timber more resistant to rot and decay.
With the Thermo Ash the resins and sugars are removed which improves durability against fungus and insect attack. A highly durable timber
Bending properties vary but normally very good. The wood is elastic, tough and strong relative to its weight and has good stiffness and hardness. Shock resistance is very good. It works well with machine and hand tools but has a tolerable blunting effect. The harder species need pre-drilling for nailing and screwing. It polishes, stains and glues well.
Normally below 8% KD
Commonly asked questions about Thermo Ash Wood
Is Thermo Ash a hardwood or a softwood? Thermo Ash is a modified wood. It is the same for; is Thermo Ash hardwood or softwood? - Thermo Ash is a modified wood.
Most groups/families of species share the same characteristics but this normally relates to their life as plants. Individual species do not always share the same characteristics as their relatives, in terms of the wood. Many factors influence how we use the wood and what we use it for, including where it grows, how it is forested, how it seasons/dries, etc. The answers to the following common questions, therefore relate to this particular species/wood and not the Ash family as a whole. Even more specific – our answers relate to the wood (as we know it) in its form as a useable resource.
What colour is Thermo Ash? Thermo Ash can be described as brown, dark brown
Is Thermo Ash good for outdoor use? or is Thermo Ash good for exterior use? Thermo Ash is most suited for exterior/external use. Thermo Ash can be used as an exterior/external timber (without treatment).
Whether the wood is naturally durable or not we would still recommend that it is decorated and/or coated with a suitable product to provide protection and/or maintain its appearance. This even applies when using the wood internally as, even subtle, changes in temperature or humidity will affect the wood. This will depend on the application/purpose of the wood and the user’s desired appearance. We also recommend that a recoating, care and maintenance programme is adhered to, for the life of an exterior wood. Wood cannot rot if it is kept dry – coatings and decoration can provide this protection. All of that said there are many durable timbers that are often left to weather naturally and will last for many years untreated/coated – movement and visual changes will occur but this is sometimes the desired effect. All wood is hygroscopic (it 'wants' to be in tune with its environment) it will therefore take on water from moisture in the air (or when directly exposed to or submerged in water) and ‘release it’ when dry or exposed to heat. This, inevitably, results in movement and dimensional change. For more about moisture in wood please click here - Moisture in wood