How to Add a Shed Roof to a Patio

On a patio, a shed roof is usually of a simple slanted style, attached to a wall of the house and sloped to drain water away from the building. Your big decision on building a shed roof over a patio is what type of covering to use. You can use wood decking covered with shingles, corrugated metal or some type of plexiglass or plastic. The basic roof structure will be the same: posts to hold the roof and some kind of support to hold the roofing.

Add a Shed Roof to a Patio
  1. Measure your patio with a tape measure and mark spots for posts. If the roof will attach to the house, you need posts at the outside corners; if it is a stand-alone patio, put posts at all four corners. You will need posts in between if the span is long -- say, over 12 feet. Dig holes for your posts, at least a third of the height of the post, and set them in concrete, making sure they are straight and plumb. If you are attaching to a wall, lag-screw a 2-by-6-inch ledger board into the house framing. Flat siding can just be covered; beveled wood or other material will have to be removed so the ledger is flush against the wall. Slip metal flashing up under the siding so it comes below the ledger board.
  2. Determine the pitch or slope of your roof, at least 1 inch per foot, and attach 2-by-6-inch side support to your ledger board, using metal joist hangers, and to your outer posts. Screw another 2-by-6 to the posts across the outer edge. Then attach 2-by-6 joists every 2 feet between the ledger board and outer board, using joist hangers. For extra support, fasten diagonal braces on both sides of the corner posts.
  3. Roof your patio. If you are putting on shingles, deck the roof with oriented strand board (OSB), cover it with roofing paper, then nail on shingles. Install corrugated metal using roofing nails to fasten panels to the joists, with corrugated valleys running downward. Overlap panels by one valley unless the panels interlock with one edge sliding into the other. Plexiglass or other plastic can be nailed to the joists. Cut either metal or plexiglass to fit with tin snips or a metal saw.

Things You Will Need

  • Tape measure
  • Posthole digger
  • 4-by-4-inch posts
  • Concrete
  • Framing lumber, mostly 2-by-6 inch
  • Lag screws
  • Hammer and nails / screw gun and screws
  • Oriented strand board (OSB) decking (optional)
  • Shingles (optional)
  • Corrugated roofing, metal or plastic (optional)
  • Tin snips or metal saw (optional)


  • Leave a little overhang on the bottom of your roof.
  • Working on roofs can be dangerous; use caution.
  • Get help lifting boards or roofing panels.
  • Use caution cutting metal roofing; edges are sharp and can cut fingers and hands.

About the Author

Bob Haring has been a news writer and editor for more than 50 years, mostly with the Associated Press and then as executive editor of the Tulsa, Okla. "World." Since retiring he has written freelance stories and a weekly computer security column. Haring holds a Bachelor of Journalism from the University of Missouri.

Photo Credits

  • Comstock Images/Comstock/Getty Images