SBWire tells MHProNews one way to increase the size of a home is by a modular addition, either vertically or horizontally. A vertical addition will increase light and add a view without having to increase the footprint of the house, which involves more foundation work. Conversely, a horizontal addition will require a larger lot without the necessity of having steps to climb. In either case, consideration has to be given to the aesthetics, existing infrastructure, local building codes, structural integrity of the existing home, as well as the comfort desired by the homeowner.
(Photo credit: National Association of Home Builders)