David Croom (right) learned at least one important thing when he was earning his MBA. "Economics can be distilled down to one lesson: Demand and supply sets the price," he says.

He has parlayed that equation into a successful construction business. Croom added remodeling to the company's new home business in 1992. Now, 66% of the company's work involves new houses and 30% is remodeling work; commercial construction jobs make up the remaining 4%.

But Croom did not want to stop there. When he noticed a need for home maintenance services for owners of vacation homes, he decided to run a separate company to handle this work, with an eye toward franchising the concept. That company, Whitehall, focuses on small jobs under $10,000.

Though the home maintenance company is separate, Croom constantly cross-markets. One-third of Whitehall clients come from existing new construction and remodeling clients. The reverse is also true: Whitehall has been a source of leads for the remodeling division. "Our clients become reliant upon us for any of their home maintenance needs," Croom says. "As a result, for remodeling ideas, they ask the Whitehall representative if Croom Construction can help them on a remodeling job." Needless to say, the answer is usually "Yes."