Walls under Existing Roof Do you have an existing patio that you'd like to enclose? Turn little used space into living space with a C-Thru Wall System on your open patio. These wall systems offer most of the benefits of the sunroom systems, with the ease of installation that comes with building under an existing structure. Turn that extra space into the office space or workout room you've always dreamed of. See more photos of new walls, windows, and doors under an existing roof For more information, or a free in-home estimate: request a quote via our online form Call 1(888)882-8811 ~ email sales@primebuilders.net