The natural graying of Lunawood Thermowood
The thermal modification process gives Lunawood its distinctive brown color and natural weather resistance for all climates — without the use of harmful chemicals. Over time, however, the brown color will naturally fade due to weather exposure, gradually turning into shades of gray. The final color can vary from a bright platinum silver to a softer, rustic tone, depending on the structure and the climate conditions it faces.
Thanks to the thermal modification process, Lunawood requires no additional surface treatments or ongoing maintenance — as long as it is installed correctly according to our official installation instructions.
Here, we showcase real-life examples of how Lunawood gracefully weathers and the many beautiful variations of its natural graying process.
Graying of Thermowood requires sufficient air circulation
Throughout the construction process, Lunawood’s installation instructions should be carefully followed to ensure a long-lasting and sustainable result. The performance of Lunawood products depends on sufficient air circulation behind the facade and deck boards, which is achieved with a ventilation gap and adequate distance from the ground. Proper air circulation prevents excess humidity from damaging the wood and helps to achieve natural gray patina, and the exterior cladding lasts longer.
Gray cladding with low-maintenance – even without any surface treatment
Thermal modification makes Lunawood highly durable, and with proper installation, it can be left untreated without any surface protection. This feature makes Lunawood an even more sustainable choice — eliminating the need for regular maintenance with oils, stains, paints, or prep work. It saves resources in many ways. If left untreated, Lunawood cladding will naturally weather to a beautiful gray over time when exposed to weather. When the goal is to achieve a uniform gray color immediately after installation, the pre-grayed Luna Arctic is an excellent solution. It provides a beautiful gray surface for projects where very little UV radiation reaches the wood — such as shaded facades and soffits.
To preserve Lunawood’s original brown color and minimize small cracks or splits over time, regular maintenance is necessary. This can be achieved by applying a tinted or pigmented wood oil, wax, wood-protecting stain, varnish, or paint — ideally containing a UV filter — to maintain the wood’s surface color.
A gradual transition to a silver-gray wood surface
The beauty of Lunawood ThermoWood® products lies in their natural, chemical-free composition and their graceful aging process — transitioning from rich brown through varying lighter and darker shades, eventually reaching a beautiful silvery gray.
To allow this natural graying, the surface should be left untreated to breathe and be exposed to UV light. No maintenance treatment is needed if the natural aging process is desired.
The natural graying of Lunawood ThermoWood® helps buildings blend seamlessly into their surroundings, while the soft, neutral tones allow for bold accent colors to be used in other materials.
Graying occurs due to physical and biological processes in the top layer of the wood. It results from a combination of factors, beginning with changing weather conditions and, most importantly, the sun’s UV radiation.
Sunlight breaks down compounds like lignin and hemicellulose, causing the wood’s surface to fade. Dirt particles, surface vegetation, and dead organic matter further contribute to the graying. The combined effect of fading and graying creates a unique silver-gray hue, with shades naturally varying from board to board — a hallmark of genuine natural wood.
How fast does Thermowood turn gray?
The duration of the weathering — or graying — process can vary widely. For example, it depends on the application: whether it’s used on a facade or decking, and how much the surface is exposed to UV radiation.
Shading from surrounding trees, structures, or solar shades also influences how quickly graying occurs. The process happens gradually and can take several years, but the end result is well worth the wait.
