adder wrote:
Mine would be three sided & I'm thinking now about how I would make
the frame rigid enough. I'm planning on the three sides being full
length glass panels more or less. Does all the rigidity come from the
roof?

No, the framing carries std. window frames which add to the rigidity,
but allows the whole thing to move as well. If ours was rigid it'd
pulled the wall down or broken by now as one corner rises and falls by
several inches during the year, due to the oak trees.....
Be wary of full length glass, there are specific safety requirements
which means a lot more expense, thats why the bottom of ours is wooden,
not glass, also hides the "stuff" stored in it!

Niel.