For design/build partners Patrick and Michael Cunningham, the divide-and-conquer principle was something like a birthright. When they were still children their father, a custom builder, pegged Patrick as an architect and Michael as a builder.

As kids, brothers Todd and Tony Groskreutz behaved like anything but partners. “When we were growing up we fought like cats and dogs,” says Tony. Todd concurs: “We definitely had our moments.” As expected, the brothers’ early career paths diverged sharply. Tony stayed close to home in Minnesota, working in corporate sales and marketing. Todd struck off for Florida, where he founded a successful Web development company, and later moved to Chicago. Then a funny thing happened. Living far apart, the brothers grew closer, and they began to impress each other. “We both became experts in our fields,” Tony says. “By then, some 20 years later, I had gained so much respect for him.” Todd, always more adventurous and entrepreneurial, convinced his brother to move to Chicago and, along with their two wives, become custom builders, a field in which none of them had much experience.

It was tough in the beginning, Tony remembers, “until we finally said, ‘You’re responsible for this, I’m responsible for that. I won’t poke my nose in your business.’” Having plenty of work helps. Even if his brother wanted to look over his shoulder, Tony says, “He’s too dang busy building houses that I’ve sold.” But the foundation of the Groskreutzes’ success has been recognizing their differences as an opportunity for cooperation rather than conflict. Todd calls his brother “an idea machine” and a natural salesman. Tony calls Todd “one of the smartest people I know” and marvels at his ability to manage a construction schedule and finesse all the relationships involved. The Groskreutzes’ business is still young, but the brothers have a grip on the fundamentals that can elude even long-time partners. “We work a lot,” Todd says. “You want to do the things that are fun for you.” The beauty of this arrangement is being able to do just that. “And getting to see your brother every day.”

Paul and Michael Schelble are limited in dividing up their responsibilities. As proprieters of a two-man company, they are seldom more than a ladder’s length apart. “One day last week,” Paul says, “he looked at something I had done, and he said, ‘Are you going to leave it that way?’” He laughs as he tells the story, and Michael laughs with him. “To a family member you can be less than courteous,” Paul observes. The key to surviving as partners is “to be willing to say you’re sorry and also be willing to forgive the other person. Because you will—you will—step on each other’s toes.” Thirty years of working together, though, can wear off a lot of rough edges, Paul says. “Ego ceases to be an issue.”

Still, a jobsite can get awfully small, and when the pressure builds, the Schelbles have a safety valve. From time to time, they simply take work independent of one another. Paul recently finished a custom home as part of an ad hoc team with two other builders. Michael does shop work on his own, “cabinetry and stuff, and I enjoy that.” Working together often, but always by choice, allows the Schelbles to keep things light. It also reflects the fact that they value each other—and the other family members who would be affected by tension between them—more highly than any business arrangement. “At some point you’ve got to realize that your brother is much more than another worker,” says Paul. With the whole web of familial relationships on the line, he asks, “Is it that important to make a living with your sibling?”