To transport large items that can be cumbersome and bulky, many car owners choose to obtain a roof rack. Roof racks, also known as cargo racks, are useful to carry items such as luggage, building materials and other items that do not fit into the car. Luggage is more commonly transported on roof racks by people driving to a vacation destination. There are various types of roof racks that are available to car owners commercially, but you can build your own, which can be less costly.
Cut two 5 by 10 cm (2 by 4 inch) wooden boards to a 1.2 m (4 foot) length with a saw. Cut three 5 by 5 cm (2 by 2 inch) wooden boards to a 60 cm (2 foot) length.
Position both 5 by 10 cm (2 by 4 inch) boards on the flat surface in your work area. Place the boards so they are parallel to each other and about 60 cm (2 feet) apart.
Lay the three 5 by 5 cm (2 by 2 inch) boards across the two parallel boards. Position the boards so they are perpendicular to the longer boards and about 25 to 37.5 cm (10 to 15 inches) from each other.
Nail the pieces in position to each other with 7.5 cm (3 inch) nails and a hammer. Secure the boards together to form the wood roof rack.
Turn over the wood roof rack to expose the underside. Apply a small amount of wood glue on the underside of the wood rack and stick felt strips along the wood. The felt strips on the underside of the roof rack will rest against the vehicle when the roof rack is installed. This will prevent scratches and other damage to the car. Allow the glue to set.
Turn over the roof rack and mount the rack to the car. The 5 by 10 cm (2 by 4 inch) wooden boards should be against the roof with the felt strips on the underside of the rack.
Secure the roof rack to the vehicle with ratchet straps. Open the front and back car doors. Pull the straps through the car and loop the straps in the rack. Tighten the straps to secure the roof rack to the car. Repeat the process to affix multiple ratchet straps through the front and back doors of the car.
Shut the doors of the vehicle and take the car out for a test drive in the city. Drive at regular city speeds and make sure that the rack is well attached to the vehicle. Once the rack is secured, take the vehicle for a test drive at highway speeds.
Have a second person help you lift the roof rack onto the car. The rack can be too heavy to lift up onto the vehicle on your own.