I built my modular , it is in 6 sections , 4 walls and a roof and the floor
I stood the base up with the floor alone and then loaded each section in the bucket of my tractor and had my wife run the lift with me in the bucket.
The roof section and was a bitch doing it alone ..
It was heavy and bulky but I got it.
All screwed and bolted together.
Its setting on solid blocks and I drove 4ft fence posts in the ground and bolted the base cross sections to the fence posts.
I wish I went bigger it’s only 4ft square but 7 ft at the peak inside .
Carpeted floor , heat and sliding plexiglass windows with a swivel office chair