Examine the structural framing of your attic to determine the difficulty of adding a bedroom. Attics that have rafters -- beams that support the roof sheathing -- rarely pose major problems to adding a finished room. However, attics that have trusses, which are W-shaped framing members that take up a significant amount of space, might prove problematic. Obtain the advice of an architect or engineer to ascertain the viability of removing or altering any trusses.
Before starting any work on your attic, review local building codes. Most local codes require 7 feet, 6 inches of head space over at least a 70-foot square area to make an attic into a living space. Local building codes also apply to the structural members of the attic, such as joists and rafters, to ensure they can safely support a finished bedroom. Most codes also require any attic living space to have a door and a window.
Consult professionals prior to beginning work on the bedroom. An electrician can tell you if the electrical panel will support the extra demand from another room. Decide whether you want a new bathroom to go along with the new bedroom. You'll likely want to hire a plumber to determine the best location for the bathroom. Consult with a heating and cooling professional to determine the best way to heat and air condition the room.
Incorporate skylights or dormers -- features that add light and open up the space -- into your bedroom plans. You may want to build a spiral staircase, rather than a straight staircase, to access the attic. Although spiral staircases cost more, they save room. An exterior staircase leading to the new room makes a good option for outside access. Check with your local building code and zoning department for their specific requirements.