Hora, door if just a bit of loglap nailed to a z-shaped brace on the back.
Front skin is thin (I think 6mm) outdoor grade ply, just bent around the frame and screwed. Sides, floor and roof are 12mm outdoor ply.
Roof was then felted, battened out and ‘shingles’ nailed on, made from bit of treated feather board, with pilot holes pre-drilled.
Window frames were scored half way through at 1″ centres on one side, so they would curve around the front skin.
There is a simple mezz floor inside too, with ladder.
All thrown together without any real measurements really, for that rustic look 🙂 You live local I think. You welcome to have a look, when you get round to doing yours.
I didn’t price it up, just kept buying what I needed. Was scary how much it cost in the end (about £500), but I suppose it could have been much cheaper if I hadn’t just kept going to B and Q.