Bob's Tip of the Day: Can your attic be converted? Habitable attic space must satisfy the same requirements that govern rooms in the rest of the house. To pass code, there must be at least 70 square feet where the ceiling height is 5 feet or higher. At least 50% of the usable area (calculated above) must have ceilings of at least 7 feet. Some homeowners satisfy this code by installing a dormer.