There are 2 main types of pergolas.
Free Standing Pergolas are not attached to any permanent structure and require its own foundation base to anchor four or more posts. The Roof of these pergolas slopes to one or two sides. These Pergolas as frequently installed in residential backyards or building rooftops.
House Attached Pergolas They use a building structure as a support to one, two, or even three of their sides. They are installed over backyard decks, terraces, and restaurant patios