Thank you all,
Golgotha, that might work , unless you have freak wind storms .... & off you'll go

. I was actually thinking of putting taut cables on the side to avoid just that but decide against it as they would be flimsy & prone to damage.
WM, indeed & reduce energy & water consumption.
I tried to use logic when I was building it. They are designed to be autonomous ( can be placed anywhere ) & off the grid. The roof is a solar energy collector. Plus underfloor electricity accumulators and also acts as a humidity collector for water reclamation by opening side nets ( will model these ). It can also have other floors underneath. So more gaming possibilities .
More will follow.
Z