Log wall sauna insulation
Many companies make sauna “kits”, which are basically log wall saunas. Interlocking logs at the corners, with double T&G logs.
These logs however are only 1.5″ thick, so they don’t have much insulation compared to an actual log cabin. This construction has drawbacks ,but they are very quick to build and ship to remote locations as well.
I’m wondering if there is a good way to insulate these. As an alternative to a traditional stick-framed build. I think it could be cheaper with materials and labour.
I’m thinking foil faced PIR insulation board inside, followed by 3/4 strapping, then 3/4 T&G. The FF PIR will hopefully be a good vapour barrier, keeping moist air in the room, and the strapping provides an air gap so any moisture behind the T&G can dry. Anything that gets through the FF foam could dry to the outside with T&G log walls?
Or could you do the same with the outside of the log walls? with an open cell foam board + strapping+ exterior siding
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There have been a lot of sauna questions here in recent years. I don't have experience with them but you might start here: https://www.google.com/search?q=greenbuildingadvisor.com%3A+sauna&rlz=1C1ONGR_enUS1048US1050&oq=greenbuildingadvisor.com%3A+sauna&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCDM0OTZqMGo3qAIAsAIA&sourceid=chrome&ie=UTF-8.
I think you could certainly do that on the inside. If I did it I think I'd do strapping on the thin timber, then FF PIR, then strapping (lined up with the other), then interior T&G. This would provide an air gap between the timber & PIR to give a better chance of drying.
Make sure to seal the FFPIR very very well though as there can be considerable pressure in a sauna that does all it can to drive moisture outward. Be particularly careful around the fresh air supply above the heater.
If you do anything other than simple timber, log or thin-timber then you must have a vapor barrier on the inside so I'd do it only on the inside.