To define a room as a legal bedroom, the space must meet specific requirements of the International Building Code and of state and local codes to make sure that it is habitable and 
safe. Whether you are converting space in the attic and basement, repurposing other unused space in your home, or building an addition, you must meet certain requirements to have a true legal bedroom.
What Codes Usually Define a Legal Bedroom
While codes vary locally, requirements for size, height, and egress are fairly standard. The bedroom:
- Must measure 70 square feet with no dimension less than 7 feet. Obviously, a hall that was 2 feet wide by 35 long cannot be defined as a legal bedroom.
- Must have ceilings no less than 7 feet high above the finished floor. For sloping ceilings, as in converted attics, 50% of the space can be less than 7 feet high, but 5 feet is the minimum height.
- Must have a window that opens for ventilation, light and fire escape. Each of these purposes has a different requirement. To provide adequate light, the window must be at least 8% of the floor area in size; while for ventilation, it must be at least 4% of the floor area. To provide a safe fire escape route, the window must have an area of 5.7 square feet, and be no less than 24 inches high, 20 inches wide, and 44 inches high from floor to sill.
- If in a basement, or located below ground elevation, must also include a window that offers a minimum clear area of at least 9 square feet and a minimum dimension in each direction of 3 feet. If the window in the room is more than 44 inches from the sill, there must be a permanently affixed ladder or steps that are fully accessible.
- Must have a closet in most jurisdictions, even if the closet is a portable one. Having a door is not required to make it closet. Even if a room is used as an office, it may still be the definition of legal bedroom.
- Must be part of the home. A bedroom located in a guesthouse or shed is not included in the total number of bedrooms in the house.
- Must have a smoke detector in the room and in an adjacent hall.
- Must have proper electrical wiring including an arc fault circuit interrupter (AFCI) to prevent electrical fires from faulty wiring.
- Must have a proper septic tank rating to accommodate additional bedrooms in developments with septic tanks. Even though the bedroom might not include a bathroom, the septic tank may need modification if adding a bedroom exceeds the rating.
Creating a Legal Bedroom
Creating a room that will be considered a legal bedroom by the city fire marshal, housing inspectors, and the appraiser requires adhering to the nine provisions listed above. To make sure you are developing a space that will serve the purpose, meet codes, and an offer safe egress, ventilation, and light, work with a licensed contractor such as Topp Remodeling & Construction.
