The least expensive renovation would be if the construction
stays within the existing exterior walls.
Another renovation requires a partial addition by
constructing a dormer i.e. raising part or all of half the roof;
usually in the rear.
Another slightly more costly renovation is to create a double
dormer both front and rear.
Then, another possibility is to remove the roof on a ranch
and add a second floor addition. There are also alternatives in
increasing the size of the second floor addition.
One addition method would be to build directly on top of the
existing exterior walls.
Another type of addition is to cantelever over the existing
front and rear walls which the codes will vary in different
states. In New Jersey, a two foot front and rear cantelever is
typical as long as the floor joists are a minimum of eight fleet
into the proposed room.