How to Change Your Two Car Garage Into a Four Car

Look through some home design books as research. Pay particular attention to the roof lines of the different houses shown. In order to expand a garage, the roof lines will need to mesh.

Carefully investigate the different angles of your roof, as well as the rest of your house. The additional garage space will need to be proportionate to the rest of the house.

Measure the yard space that will be necessary to build the garage addition. Remember that you are doubling the size of the garage, so be sure to measure the dimensions of the garage, then measure those same dimensions in the yard. If possible, place wooden or metal posts in the yard to mark the area where you have measured.

Begin constructing a blueprint or floor model of what your new garage space may look like. Remember to keep in mind the roof line and other various angles on the house. Carefully craft a sketch of the new garage that will blend in with the rest of the house and look as if it's always been there. Include an exit door (if one does not already exist) in the blueprint, in case of fire.

Begin building a concrete foundation based on the measurements you took earlier. Use 2 x 10 lumber to construct the footings. Lay two rows of cinder blocks on top of the footings, for cinder block walls. Be sure to leave drive-in space for the cars when doing this. Also leave the desired space for an exit door. Lay metal gridwork for the floor area before having any concrete poured.

Begin constructing the additional wall and roof area. Lay cinder block walls, leaving openings for window space, if desired. Build a framework for the roof additions. Leave room for the central wall area to be removed.

When building the new roof rafters, use metal support posts to shift the weight once held by the previously removed wall. Add bricks to the exterior wall area. Cover the roof area with 1/2 inch plywood, then place Asphalt shingles on top of the plywood. Add the stalls for the roll-up garage door (or doors).

Add the exit door to the garage. Install the metal tracking for the roll-up garage door with an electric screwdriver. Install the new door.