How to Build a Carport With a Shed

Design the carport for the height and width of the vehicles for which it's being built. Use the width of the existing driveway as a starting point. Plan the shed to be the width of the driveway with a roof that slopes away from the carport. Use the front wall of the shed as the high point for the carport roof.

Build the shed first. Make two side walls 8 feet long with 2-by-4-inch top and bottom plates. The top and bottom plates are 2-by-4s at the top and bottom of the wall to which studs are secured. Space wall studs every 16 inches. Raise the walls and brace them temporarily with boards nailed to studs and to stakes in the ground. Using a level, get the walls plumb. Secure them to the driveway with a hammer and 4-inch concrete nails. Measure the distance between the walls with a tape measure. Construct the front and back walls to those dimensions, again using top and bottom plates secured to studs.

Frame a door in the front wall. Put a horizontal 2-by-6-inch header board between two studs at the height for a prehung door and nail it from the sides. Cut shorter studs from the bottom of the header to the bottom plate and nail those to the side studs and the header. Cut off the bottom plate inside that opening with a reciprocal saw. Add short studs atop the header between it and the top plate.

Raise the front and back walls. Set them plumb and nail them to the driveway with concrete nails and corner studs together with framing nails. Add cap boards on top of the top plates so the front and back caps overlap the end walls and the end caps fit between. Add two more cap boards on the front wall to provide a slope for both shed and carport roof.

Sink 4-by-4-inch pressure-treated posts at the edge of the driveway to support the carport roof. Space them 4 feet apart, starting at the front wall of the shed; that will make a carport 16 feet long. Use a post hole digger to dig holes a third the height of the finished post. Set the posts in the holes, starting 3 1/2 inches below the height of the shed roof. Plumb the posts and temporarily brace them. Fill the holes with concrete around the posts to secure them. Let the concrete set for at least three days.

Use a string line to mark a slope along the posts from the shed roof to the end. Make a slope of at least 4 inches from the shed roof to the end post. Mark those angles and cut the posts with a reciprocal saw. Lay 4-by-4-inch beams on top of the posts from the shed to the end post. Fasten them with framing nails toenailed at an angle into the vertical posts. Cut 4-by-4-inch posts at 45-degree angles on both ends to make braces on each post between the post and the top beam. Nail those in place.

Measure the width from beam to beam with a tape measure and cut 2-by-4-inch rafters to fit. Install the rafters with metal hangers nailed to the beams. The metal hangers support the rafters, which are nailed to the hangers from each side. Space rafters 24 inches apart between the shed roof and the end posts.

Install corrugated metal roofing on the carport, starting at the bottom. Use two sets of panels, one set 8 feet long, the other 10 feet. Put the bottom panels in place, overhanging the roof end about 6 inches. Secure them to the rafters about 18 inches apart using a screw gun and screws with plastic washer caps. Overlap panels side to side according to manufacturer's directions. Add a second set of panels atop the first to extend to the shed roof, overlapping the bottom panels by at least 6 inches. Cut panels to fit if need be with tin snips or a metal saw.

Use 8-foot panels to cover the shed roof, sloping away from the carport. Finish with special ridge caps where the carport and shed roofs meet. These are corrugated metal sections which overlap the roof joint to seal it. Attach ridge caps with screws on each side of the peak.

Cover the shed walls with exterior grade plywood. Use two 4-by-8-foot panels on each end and as many as required on front and back walls. Get tongue-and-groove panels which interlock to seal joints. Use a circular saw to cut panels to fit. Install a prehung door in the rough door opening. Put 1-by-4-inch trim boards on all corners, two boards per corner with the sides overlapped, and around the wall tops. Trim the door with 1-by-4s on the side and top of the frame.