Timely thread.
I've been considering building one for the back yard.
Will most likely look like a small shed or backyard studio with a changing room and a hot room.
Probably overkill, but not quite sure how I would fit into my basement.
This guy has a pretty decent site / blog.
I have not 'subscribed' to his membership deal - but I did buy the e-book.
http://saunatimes.com
I'm thinking 8x12 with LP smart side exterior. Probably a single slope roof.
Most likely will build on skids - it won't be a 'structure' then.
Wife is really interested in having one. Think it would be a nice step after a workout.
If I am able, I may add another 4' long section as an exterior shed. Get some of the lawnmower and snowblower type stuff out of the garage....