Here, our roofing experts explain how to attach a patio roof to an existing house. Beginning from the roof to the house (not the house to the roof), calculate the sightline clearance height. After that, determine the beam size you’ll want to use. Then, choose a roof pitch and roof structure.

This patio roofing style attaches to your home and uses your home’s structure as support for one side. Then the other is supported by beams. You can then complete the roof portion of your lean-to with a construction method that works best. You could add metal roofing, timber framing, or wood paneling, depending on your patio design.

A lean-to or shed roof is typically a single, flat sheet of material attached to the house’s side and installed on a downward slope. It’s one of the simplest, most cost-effective permanent patio roof options, but also one of the least aesthetically appealing. These roofs are usually made of aluminum or wood and cost about $1,400.