Dig a footer around the exterior walls of carport. This will be the walls that are not joined to the house. A footer is a trench that is dug around the outer walls of a structure that is concreted; the concrete blocks of a structure are built upon the footer.
Using mortar and blocks that match the blocks of the house, lay the blocks around the exterior walls of the carport. In laying the blocks, make sure the blocks line up with the house's blocks.
Use a tape measure to ascertain the length of framing lumber needed to construct the exterior walls. Measure the lengths to match the exterior wall of the house.
Use a table saw to cut the framing lumber to the measured length.
Hammer the framing lumber to the exterior wall to connect any space that may exist between the closed-in carport and house. This will connect the house and the carport.
Nail plywood or OSB sheathing to the exterior walls.
Attach matching siding to the sheathing.
Take the tape measure and measure for the roof structure. To ascertain the proper length for the rafters, measure a straight line from the peak of the house's roof to the peak of the carport's roof.
Use a table saw to cut the rafters to the correct length.
Use lumber for the rafters and build a roof that will slope from the top of the house's roof and will be connected to the far slope of the carport's roof. The new roof should connect directly to the carport's roof, giving the appearance of one roof. A ladder will be needed in this step to reach the roof.
Apply roof decking to the rafters with a hammer.
Apply tar paper to the top of the roof decking.
Nail in matching shingles to the decking through the tar paper with the hammer. If applied correctly, there should be no sign that the carport roof and house roof are two different roofs.
Apply shingles to the roof joining the house to the carport, using shingles that match the shingles on the house.