[timelord (Al)]

Gooday I.C.D, As the purlins sit directly on the top rails of the colorbond rails, these two sides need no further sealing as they fit snugly.(maybe a thin bead of silicone sealer if req'd)
The front closing edge in my case fits and butts up against and under my deckings veranda guttering but you could easily employ a fascia panel if yours will be free standing. The rear closure employs a drop down panel from the roof which slides open with the roof and also seals to the top rail of the colorbond fence top rail.
A simple rubber strip completes the weather proofing here. Rubber sheeting cover the gap left by the pitch of the roof to the purlins which also slide with the the roof.
The flooring is made of timber (tongue and groove pine floor boards. The floor is completely isolated from the pier's concrete foundation. I still have some dust issues with the open ends of the purlins and will resolve these shortly when I come up with an idea!
I'll post some more photos relevant to these items tommorow If I can, hope this helps.
Al.