If you would like a sitting area on the deck to have some roof, put a gazebo on the deck is a very good choice.
In this case, we put a prefabricate gazebo on our custom designed deck, we shape the deck area to a octangle shape, to match the base of gazebo and we made new railing for the gazebo to match the deck railing, so after everything is done, the gazebo looks like a custom build one, not a prefabricate one.
This saves my customer thousands of dollars, with a excellent appearance~~