Enclosing a car port to make an additional room, if done properly, can add square footage to the home. If the car port has ducting run to it and the proper amount of wall sockets, and is done under permit, it can add significant value to the home. In order for the new room to be considered a bedroom, in most areas of the United States, the room must have a closet. A bedroom may add more value to a home than a "bonus room," depending on the location of the home.
Clean the flooring of the carport off. For each area that is not butted up against a cement pad, build a form from 2 by 4-inch boards to hold the concrete. Use stakes outside of the form to hold the form in place. Contact a cement dealer to come in and pour the cement flooring, so that it is level with the flooring of the home. Allow the cement to cure pursuant to the manufacturer's instructions.
Measure the width, length and height of the car port. Build the frames for the walls. Build the walls using 2 by 4-inch boards. The wall studs should be 16 inches apart. The longer walls will need two or three separate frames (depending on the length of the wall), which are then nailed together using 2 by 4-inch boards across the top and bottom. Place a chair between the studs at every 3-foot mark.
Bolt the frames into the cement flooring using lag bolts. Use 2 by 4-inch boards to sturdy the walls, if needed. Use long screws to screw the top of the frame into the existing car port roof.
Cover the outside walls with plywood, then the material of choice such as siding or stucco. If you made the frame to include windows, install the windows.
Wire the outlets if you are adding more wall outlets. Depending on what county and state you are in, you may have to hire an electrician to do this. Most states requires an electrician to sign off on the work if you do it yourself. Add insulation between the studs.
Hang drywall on the inside frames. Paint or wallpaper the drywall. Finish with the floor cover of your choice (carpeting, tiling, wood floors).