How to build a one-sided carport

Updated February 21, 2017

A carport is a useful addition to any home. Not only does it shield a vehicle from the elements, it also can add to the value of the home. Nestling a carport up against one side of the home makes this project fairly simple to accomplish, since you are only adding on a roof line that is supported by posts on the outer wall. If the roof of the carport is going to be covered in the same type of material as the house roof, it's best to match the slope of the carport roof to the rest of the house.

Check with local building authorities to confirm the height, type and location requirements for a carport, and whether you need a building permit. Stake off a location for the carport, usually 9 by 18 feet.

Dig holes for the posts at all four corners and one more in the centre of the outer edge of the carport. The posts should be anchored at least 2 feet into the ground, or more, depending on your local building requirements. Add six inches of concrete mix, place the posts and check for level and plumb. Brace the posts. Fill the remainder of the hole with concrete mix and let it dry.

Attach a beam horizontally across the top of the posts at the outside edge of the carport. For extra support, attach another beam on the inside edge of the outer wall. Attach a ledger board on the house side at the same height, using bolts. Attach beams from the outside corner posts to the house-side posts.

Hang the joist hangers onto the ledger board and nail them in place. Do the same on the inside edge of the outer wall. Slide the joists into the hangers and nail in place.

Measure up on the house side wall the amount of slope you want for the roof and nail a beam horizontally. Seven beams will be needed for a standard carport. To achieve the necessary overhang, notch out one side where the beam will fit over the outside wall. Saw down the other side to form an angle for the proper slope. Nail the beams into place.

Check the diagonal dimensions of the carport to make certain that the structure is square. Nail steel roof braces at each corner across the top of the beams.

Install plywood and roofing shingles, or metal roofing. Add flashing on the house side for a waterproof seal, and a gutter on the outside wall for drainage.


Add a gravel bed or concrete slab under the carport for extra durability.

Things You'll Need

  • Pressure-treated posts
  • Post hole digger
  • Shovel
  • Concrete mix
  • Level
  • String
  • Stakes
  • Hammer
  • Drill
  • 2-by-12-inch ledger board
  • Joists
  • Joist hangers
  • Beams
  • Nails
  • Bolts
  • Corner braces
  • Plywood or metal roofing
  • Roofing felt
  • Shingles
  • Flashing
  • Gutter
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About the Author

Becky Lower began writing professionally in 2004. Her work has appeared in "elan" magazine, a northern Virginia publication, "Good Old Days" magazine, the "BGSU Alumni" magazine and on the website Lower has a Bachelor of Arts in journalism and English from Bowling Green State University.