How to Build a Wooden Carport

Park the car or cars that will be housed under the carport in the spot you want to build the carport. Lay out the posts of the carport around the cars. Place a post on either side of the driveway about 2 feet behind the end of the longest car and 2 feet from the side of the cars. Place a post on either side of the driveway about 2 feet in front of the longest car. Add a post in the middle of the two posts on each side.

Dig a hole for the the footers of each post. Make the holes 2 feet deep and 1 foot in diameter. Post hole diggers are much easier to use for this than a shovel.

Insert a 4-by-4 post in each hole. The posts at the front of the carport should be 11 feet tall, and the posts at the back of the carport should be 10 feet tall. Fill the footer holes with concrete, using a shovel handle to pack it in around the post. If middle posts are present, use 11-foot-tall posts.

Check to see that the two front posts are level. Place a board across the tops of them and place a level on the board. If the posts are not level, select the one that is shorter and level over to the taller post using the board and level again. Instead of placing the board on top of both posts, only place it on top of the shorter post. Let the board ride along the face of the taller post and adjust its position until the board is level. Make a mark at the level point. Cut the post at the level mark to make the front posts level with each other. Do the same with the back posts. To determine the height of the middle posts, run a string from the front post to the back post and cut the middle post where the string crosses the post.

Measure down 11 1/4 inches from the top of the front two posts and mark the side of the post that faces the other front post and the side that faces the middle or back post. For middle posts, make a mark 11 1/4 inches down from the top on the two sides that face the front and back posts. On the rear post, the marks should be on the sides that face the middle or front post and the other rear post.

Measure the distance from the outside corners of the front and back posts on each side. Cut a 2-by-12 to this length. If there is a middle post, measure from outside of the front post to the middle of this post and from the outside of the back post to the middle of the middle post. Cut a 2-by-12 for each dimension.

Nail the 2-by-12 boards to the posts on each side of the carport. Align the bottom of the boards with the marks made in Step 5. After nailing the boards to the posts, use a 1/2-inch auger bit and drill two holes through the 2-by-12 and each post. Insert galvanized lag bolts through each hole. Fasten each bolt with a washer and nut.

Measure the length between the outsides of the front of the 2-by-12s and the rear. Cut a 2-by-12 to each length and nail them to the front posts for the front side and the rear posts for the rear side. After nailing, replicate the process from Step 7 to insert lag bolts through the posts.

Install the joists. Measure the distance between the two sides and cut the 2-by-10s to this length. Start at the front and install them 16 inches on center. Nail through the 2-by-12s into the 2-by-10s with four nails in each board.

Nail 4-by-8 sheets of 1/2-inch plywood on top of the joists to create the roof deck. Start at a front corner with a full sheet of plywood. Overlap the edges of the roof framing by 1 inch. Continue installing plywood sheets, working your way to the rear of the carport until the first row is done. The last sheet needs to be cut to fit. Install it with the cut side against the previous piece and the factory edge on the outside of the structure. Start the next row with a full sheet, but on the opposite side of the roof so that the seams don't all fall on the same joists. Continue this process until the roof is completed.

Nail aluminum drip-edge flashing along the perimeter of the roof.

Install roll roofing with the roofing running from side to side. Start at the rear of the carport, as this is the lowest point of the roof. Roll roofing cement on the roof and apply the roll roofing to it. Overlap the edge of the flashing by 1/2 inch. For the next row, overlap the bottom row by 3 inches. Apply roofing cement and place the roofing down. Continue until you finish the roof.