Does your home have a large, undeveloped attic just waiting to become living space? Many houses do. Key ingredients are ample headroom and the ability to install stairs for access.

Of course, many improvements are necessary to make an attic livable, such as strengthening the floor, moving heating or air-conditioning equipment, installing insulation, bringing in natural light, finishing the surfaces, and providing power, heat, and--often--cooling.

Be sure to check local codes and apply for a building permit before beginning an attic conversion project. You'll have to pay particular attention to rules about structural loads, minimum headroom, stair access, and emergency escape routes. For example, because the ceiling typically slopes in an attic, codes often call for 7 1/2 feet of clearance across at least half of the floor area. Also, because the floor joists in an attic are intended for light-duty use (holding the ceiling below), they frequently need reinforcement. In planning any structural work, including removing crossbeams or other roof supports, be sure to get the advice of a structural engineer.

Because most attics don't have windows, introducing natural light is often a challenge. Gable-end windows and skylights are good solutions. Though building a dormer calls for major roof work, this will improve both attic headroom and natural light.