The flat roof of an orangery is constructed with glulam beams to form a perimeter around the roof of about 500mm to 1000mm in width, leaving a large central opening. The flat roof section is made with roof joists, over which insulation and ply decking is fitted. The roof is made waterproof with a lead colour fibre glass, built with a slight fall so that water will run down to outlets or directly into a gutter. Inside the flat roof, down lighters can be incorporated into the interior lighting design.
