The soil is clay.
I'm thinking building it as a temporary structure 1m away from any other walls and fences and less than 1 storey to avoid any planning permission. No running water. But electricity yes. Solar panels yes.
I want to make it stand above the clay.
So make concrete post holder that are about half meter square with a pair of holes using a custom made mold, and then dig up the clay to plant the concreate post holder. Then wrap some plastic and insert big pair of vertical wooden poles every few meters.
To make wall, I can slip in additional timer and sealant between the vertical wooden poles. (I didn't want to use lapped wooden wall - just don't like that type of appearance.)
The roof is outdoor plywood covered with felt and whatever else to make it water proof. Plan to fit solar panels on the roof.
Any good as an idea?
May be design it using openscad scripted 3D and some dxf drawings to get a grip on materials sizes, and alignments.