While it is structurally sound, and looks very nice in my opinion, there are areas where the beams had twisted or were slightly warped, and as such, the fit between them allowed for many small gaps and irregularities.
The inside bare logs weren't the nicest to lean against. They were rough cut, and there were about three or four gaps of up to an eighth of an inch. As well, there were spots where one beam was almost a half inch offset from the beam directly above or below.
These added up to a decision made already a year ago that I would be panelling the inside of both the sauna and the cabin to make the interior more uniform. The other pleasant side effect was that I would be able to add more insulation, and a vapour barrier.
The priority was the sauna - we want it to stay warm enough to keep the water tanks liquid for up to 48 hours at a time. This also gave me the opportunity to test my techniques before applying them to my cabin.
I was able to score very inexpensive 1x2 straps from the local Home Depot. They were cheaper than petrol in my own sawmill!
They were 5/8 of an inch thick, which was a worry when I was first looking at 3/4" insulation. Luckily I was able to spot nearby a stack of 1/2", 24" x 96" foam panels. I purchased a small amount of both items and headed home to begin.
First up was to strap around the outside of each wall. I used Kenny's mining hammer to coax the straps as tight as possible into their positions.
I also needed to remove the existing framing around the windows and doors to let me install the more regular straps. Also - the supports for most of the benches.
It was nice to fit the panels into place. Very much like Tetris or Lego or something along those lines.
I really like how it has made the sauna feel cleaner and warmer. In the change room and washing room, I will use a standard vapour barrier with pine panelling. In the steam room I have only added insulation to the wall without the stove and will switch to cedar panelling. The stove wall will only have a vapour barrier and cedar.
In the steam room I will ensure that the vapour barrier is foil all around. Most sources seem to suggest that a plastic vapour barrier in the presence of the heat and steam is not a good idea.
Stay tuned to see how this develops - my current source for cedar panelling has already told me they are not able to supply any more any time soon, so I may have to try to match as best as I can.