An orangery will feature a lot of solid walling, columns and pillars, which is why they very often need planning permission because they are less than 70% clear or translucent buildings.
Fancy roofing is also a design feature with a lantern glazed section built into the centre of a flat roof. Around the edges of the flat roof are detailed cornices and hidden gutters. (useful info here: How Much to Put a Tiled Roof on a Conservatory?).