You may not even need a builder for this one. Some companies like Centurion DIY Conservatories offer a self-build conservatory pack.
It’s a cheap, easy way to increase space in your home. Conservatory Prices 2018
The Four Most Common Home Extensions
Orangeries, Garden Rooms and Sun Rooms
An orangery has a more solid base than a conservatory where the brick and flint parapet walls give the impression of height. This is characterised by the addition of a lantern roof, to give a distinctive shape and allow the light to flood in.