For several years our company has specialized in adding second stories to some of the average and often humdrum ranch homes that crowd the northwest suburbs of Chicago. Many of these homeowners, faced with a growing family or a desire for more space, cannot afford the larger homes in their neighborhoods. Yet they are not willing to give up their proximity to the city and their jobs for the lower prices they'd find farther out in the suburbs. Building up, rather than out, can double the square footage of a house without taking up more of the yard. Most of the homes we work on average about 1,200 square feet, so adding onto the first floor makes the house sprawl.