If you watch home renovation shows at all, you will be familiar with the scene. The contractor and homeowners are tearing down walls of a decades-old "craftsman" home. Sledge hammers fly, plaster and drywall crumble as the team works to achieve that open concept the homeowners want so badly. Suddenly, the contractor stops. He holds up a hand -- the homeowners pause and look at him with concern. "That's not good," he says. How much will this cost, whatever it is? Commercial break.