Today is the day I bought wood cladding for the sauna. There are several types of wood you can use within a sauna, such as aspen, alder, spruce, and cedar.
Aspen and Alder are most often used for saunas in the EU, but are also most expensive. I've asked for quotes for wood, and they ranged from £300 to £600.
In the end on ebay I found a merchant selling waney cedar wood for £3 per board, 20-30 cm wide, 1 cm thick, and 240 cm long. Perfect! I got a deal for 50 boards between 15 and 30 cm, and he was so kind to saw it off to 2 meters so it fit in the car. This came to the total cost of £100, a bargain!
Apparently Cedar is used in the US a lot for saunas. It has natural antifungal and anti-bacterial properties and feels 'cool' when you touch it, very important in a sauna. This type of wood has great patterns.
It also cost me a total of 4 hours of driving :S but I had an audio book to listen too so that was fine
Look at these lovely patterns, and it smelled great too, all the way back home.
I sacrificed two of the boards to make battens to later affix the wood to. The battens are spaced about 50 cm apart. The idea here is that there is some air behind the wood so that if the boards get wet they also get a chance to dry out again, so that the back of the wood is not wet. If one side is wet and the other dry, then there will be a temperature difference if the sauna is running, and the wood will warp. There will always be a temperature difference of course, but the warping effect should be less if the wood is completely dry through and through.
The wood is freshly cut, probably some days ago, so it's pretty sappy:
So ideally the boards should dry for a while before putting them in the sauna, because they will shrink over time. But perhaps I can 'kiln dry' them in the sauna itself by heating up the stove... but that increases the risk of the boards warping. I'll just have to try one to see how it behaves I guess.
I put up one board to dry above the stove, and I've taken some measurements:
length: 55 cm, width 21 cm, weight 536 grams.
If the wood is wet then it should get lighter over time, and possibly shrink.
Unfortunately I'll have to wait with sanding down the boards until I've got some new sanding belts.