Thermo Alder Sauna Wood

Thermo Alder Sauna Wood: Alder, Black Alder, Alnus glutinosa

What Makes Thermo Alder a Good Choice for My Sauna?

Our customers often ask us “what differentiates thermo alder from our regular alder when choosing a sauna wood?” Thermo alder is a grade A sauna timber that goes through a chemical-free thermal modification process, which improves the natural qualities of alder, alnus glutinosa in Latin. This makes thermo alder a great wood choice for the hot and humid conditions of a traditional Finnish sauna. As all Finnmark alder timber products, our thermo alder is ethically sourced from Finland and the Baltic countries.

Thermal Modification

Thermo alder is a popular sauna wood type for its warm hazel brown colour, straight grain and low risk of warping. It does not knot or weep resin. Our thermo alder is sustainably grown in the Nordic and Baltic forests, and is thermally modified in these areas.

Thermo Woods such as thermo alder are popular in sauna construction, as thermal modification enhances the natural qualities of the wood. The raw wood is modified using heat and steam, which decrease its density and weight, making it easy to work with. During this process, the dimensional stability of alder is improved, the sauna wood becomes highly resistant to decay and its thermal insulation capacity is increased.

Thermo alder is a great wood choice for any commercial or home sauna that is in frequent use, because it can withstand the fluctuating moisture levels and does not get too hot to touch. Thermo alder has a pleasant toasted aroma and a beautiful golden, sometimes hazel brown colour.

Thermo alder is a great sauna timber choice where a modern, warm aesthetic is desired. As all thermo woods, thermo alder doesn’t show dirt as easily as many other sauna timber types, making it easy to maintain a clean look in the sauna.

Thermo alder has many uses in the sauna including sauna cladding, bench boards, bench skirting, sauna buckets and sauna ladles.

The recommended wastage allowance:
Thermo alder is a reasonably durable timber with no knots and a very low risk of splintering. As such, we recommend a wastage allowance of 15% for thermally modified alder sauna cladding and bench boards. This also takes into account any potential risk of damage that can occur during transportation. It is also good to note that the effective width of the cladding is slightly lower than the actual width of the sauna cladding panel. For this reason opting for a larger profile for your sauna installation.

Thermo Alder is available in the following sauna timber profiles and dimensions:

STS4 Profile Tongue and Groove Sauna Wood Cladding: 15mm thick by 68mm, 90mm, 120mm and 185mm wide
STP Profile Tongue and Groove Sauna Wood Cladding: 15mm thick by 68mm, 90mm, 125mm wide
STEP Profile Tongue and Groove Sauna Wood Cladding: 27mmx64mm
SHP Thermo alder sauna wood bench boards: 28mm thick by 90mm and 140mm wide

To further improve the longevity and hardiness of any sauna wood, we recommend treating your thermo alder cladding and sauna bench boards with paraffin oil.

You can find our selection of thermo alder sauna wood products below.