How to Build an Open Carport

eHow may earn compensation through affiliate links in this story.

Things You'll Need

  • 6 posts

  • Beams

  • End rafters

  • Rafters

  • Level

  • C-clamps

  • Galvanized bolts

  • Galvanized nails

  • Galvanized joist hangers

  • Galvanized angle bracket

  • Concrete mix

A carport is a simple structure that many homeowners have installed as a way to protect their vehicles from the elements. Carport roofs are generally a flat surface, so when building a carport you need to ensure that the grade of the roof isn't completely flat; otherwise, rain will pool on top and damage the carport. Building the roof at a slight angle will allow rain and snow to slide off easily. Before starting construction, find out if there are any building permits that you need to get.


Video of the Day

Step 1

Mark the outline of the carport. The dimensions of this plan are 10 feet by 20 feet. Dig holes for the posts. Three posts are needed along each side (one every 10 feet). The holes should be wider on all sides than the posts and approximately 24 inches deep.

Step 2

Set the posts. Fill the first 4 inches with concrete then insert the poles. Make sure the poles aren't touching the sides of the hole, then fill it with concrete, leaving the last two inches unfilled. Check to make sure that the posts are plumb while the concrete is still wet.


Step 3

Trim the posts. Mark the top of the front posts 7½ feet above the ground and the back posts approximately 4 inches shorter. String a line between the front and back posts to determine the height of the middle posts. Cut off the tops.

Step 4

Cut two 20-foot beams. On the inside edge at each end of the beams, cut a 45-degree angle. Clamp the beams to the posts, making sure that the tops of the beams are flush with the tops of the posts. Attach the beams to the posts with galvanized bolts. Predrill two holes into each post and insert the bolts. Once all the bolts are fastened, remove the clamps.


Step 5

Cut two 10-foot end rafters with the same 45-degree angle as the beams. Fix them to the ends of the beams with nails, checking that the corner is square (a 90-degree angle). Nail a galvanized angle bracket into each corner to act as an anchor.

Step 6

Cut six 9½ foot intermediate rafters. Place a galvanized joist hanger every 3 feet. Check that the rafters are flush with the tops of the beams then secure them to the joist hangers with nails.

Step 7

Install the roofing material. Nail the roofing material to the rafters. For added strength, you can use screws along the edges.


Because the footings are set in concrete and the beams are bolted to the posts, the structure doesn’t need to be braced along the sides, allowing for an open carport.