Craft · 30 June 2026 · 5 min read
Why We Only Use Thermowood for Our Outdoor Saunas
Every outdoor sauna we build is made exclusively from Thermowood. Here is the reasoning behind that decision.
Thermowood is timber that has been treated with nothing but heat and steam. Temperatures above 200 degrees change the structure of the wood itself, removing the sugars and resins that fungi feed on and driving out moisture that would otherwise cause movement.
The result is a material that resists rot, stays dimensionally stable through a wet British winter, insulates better than untreated softwood and holds a deep, even colour.
We offer no cheaper alternative because we would not build one for ourselves. Standard spruce cabins look identical in a photograph and behave very differently after three winters outdoors.
It is also a genuinely clean process. No chemicals, no preservatives, no treatment to leach out over time. Heat and steam, nothing else.
