Thermowood is softwood that has been thoroughly treated through heat & steam to produce an outstandingly resistant timber.
Like Cedar, Larch and other timbers Thermowood will still silver overtime if left untreated.
Enjoy the depth of brown tones. Generally the longer the timber is heat & steam treated the darker the tones become.
Cost effective solution
There is more to subfloor preparation than these points so always check with your fitter, the manufacturer or us for further help.
Here are some useful installation guides that go into more depth: