When I look-up cedar boards on various home center web sites, I see many choices, but I'm not sure which most closely matches the typical sauna prefab and pre-cut kits. My situation is such that a standard kit would not fit, and it seems custom kits are not being shipped quickly, I want to get started quickly, so I don't want to buy a kit. Some sauna stores offer just the planks, but those are the same stores that are not offering quick shipping, so I thought I'd look at large home center stores that are able to ship within a day or two of ordering.
Wood available at the home center stores include 1"x6"x8'six pack of "siding", but that looks rough (not planed), and I think the standard sauna cedar is smooth. Then there is 1/4" x 3 1/2" x 8' generic "cedar", "v-plank", but I wonder if that's thick enough. There's also 1/4" x 3 3/4 x 48 "eastern red cedar" "planking", which looks really nice, and most like the wood in the kits, but is only 1/4 inch.
From a kit description:
Tongue & Groove Western Red Cedar Boards are knot-free Grade A and Better, Vertical Grain and kiln dried. This 1/2 thick (nominal 7/16") by 4" material has a 3 3/16" face (actual wall coverage).
The kits also might use even thicker boards:
3/4" thick (nominal 11/16")