The Minimum Size for an Attic's Access

For many homeowners, attic space is an essential part of the home. Although the attic may be where your heat, air conditioning or hot water unit is located, if you add flooring, you can utilize your attic for storage, as well. Building codes provide specific guidelines for attic access in homes. The type of attic access determines the means you can install for entrance into the attic.

According to the 2006 International Residential Code (R807.1 Attic Access), homes with combustible materials in the ceiling and roof construction must have an access to attic areas that exceeds 30 square feet and with a vertical height of 30 inches or greater. The rough-framed opening must be a minimum of 22 inches by 30 inches. Unobstructed headroom of at least 30 inches must be available above the attic opening. If mechanical equipment or appliances are housed in the attic, there must be an unobstructed passageway large enough for the removal of the appliance.

The attic may be accessed through a scuttle door or attic hatch, usually located in a closet or main hallway. A portable ladder is needed to provide access through such an opening. You can also install a pull-down ladder to provide ready access to the attic. The ladders, constructed of wood or aluminum, fold into the ceiling when not in use. Telescoping ladders are useful when the attic access is located in a small space, such as a closet or small hallway. A knee-wall is a partial height door found in homes with a second floor and finished attic. The doors should be insulated, weatherstripped and equipped with a latch to pull the door tightly against the weatherstripping and frame to seal the opening.

Attic access can be located either in the conditioned area of the home or in an unconditioned area, such as a garage or porch. Attic access located inside the home must be readily accessible, such as in a main hallway or within a closet.

When attic access is in a conditioned area of the home, insulation is needed. Heat can escape during cold weather, while outside heat can enter the home during the summer, both of which can drive up heating and air conditioning usage and costs. In addition, without proper insulation, attic space may develop excess moisture, leading to the growth of mold and mildew. Building codes in most states require you control air leakage into your attic through caulking, weatherstripping and insulation to conserve energy and inhibit the growth of mildew. If your attic access in an unconditioned area of your home, insulation is not needed.