Revisions log for Answer #2739

I don't think 19k is too expensive, and the decision sounds neat. For a conservatory, I would always opt for roof shading, and for an under-roof patio, it's fine. Glass with switches is interesting, but doesn't cut costs.

The polycarbonate stuff was used over my parents' patio. It was fine there because the transparency of the roof wasn't important for brightness in the house. But if the patio roof needs to be transparent in the winter to let light into the house, don't use polycarbonate. The patio was much cooler under the polycarbonate roof than in front of it – things didn't reach the level of the sun canopy or even the shade from the tree.