Rules for building and using tiny houses

Appendix Q is deleted in its entirety and replaced with the following: “APPENDIX Q TINY HOUSES SECTION AQ101 GENERAL AQ101.1 Scope. This appendix shall be applicable to tiny houses used as single dwelling units and tiny houses that contain a loft. Tiny houses shall comply with the International Residential Code except as otherwise stated in this appendix. AQ101.1.1 Limitations. Tiny houses shall not contain more than one loft, or loft space. Tiny houses that contain a loft may not be used for any purpose other than as a detached single-family dwelling. SECTION AQ102 DEFINITIONS AQ102.1 General. The following words and terms shall, for the purposes of this appendix, have the meanings shown herein. Refer to Chapter 2 of the International Residential Code for general definitions. EGRESS ROOF ACCESS WINDOW. A skylight or roof window designed and installed to satisfy the emergency escape and rescue opening requirements in Section R310.2. LANDING PLATFORM. A landing measuring two treads deep and two risers tall, provided as the top step of a stairway accessing a loft. SUPP. 11 (1-2022) 5B-42 RESIDENTIAL BUILDING CODE § 5B-3-3 LOFT. Any floor level located above the main floor and open to it on at least one side, with a ceiling height less than 6 feet 8 inches (2032 mm), complying with the area, access, and guard requirements of Section AQ105, and used as a living or sleeping space. TINY HOUSE. A dwelling which is 500 square feet (37 m2) or less in floor area excluding lofts. The maximum total floor area of 500 square feet shall mean the sum of the horizontal areas of each floor of a building measured from the exterior faces of the exterior walls. The total floor area shall include enclosed attached accessory structures such as garages or storage areas. Unenclosed attached structures such as carports, breezeways, lanais, or porches shall be excluded. SECTION AQ103 FOUNDATIONS AQ103.1 General. All exterior walls shall be permanently supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approved structural systems pursuant to Chapter 4 of the International Residential Code, which shall be of sufficient design to accommodate all loads according to Section R301 and to transmit the resulting loads to the soil within the limitations as determined from the character of the soil. Footings shall be supported on undisturbed natural soils or engineered fill. SECTION AQ104 CEILING HEIGHT AQ104.1 Minimum ceiling height. Habitable space and hallways in tiny houses shall have a ceiling height not less than 6 feet 8 inches (2032 mm). Bathrooms, toilet rooms, and kitchens shall have a ceiling height not less than 6 feet 4 inches (1930 mm). No obstructions shall extend below these minimum ceiling heights including beams, girders, ducts, lighting, or other obstructions. Exception: Ceiling heights in lofts are permitted to be less than 6 foot 8 inches (2032 mm). SECTION AQ105 LOFTS AQ105.1 Minimum loft areas. Lofts used as a sleeping or living space shall meet the minimum area and dimension requirements of Sections AQ105.1.1 through AQ105.1.3. 5B-43 SUPP. 11 (1-2022) AQ105.1.1 Minimum area. Lofts shall have a floor area of not less than 35 square feet (3.25 m2). AQ105.1.2 Minimum dimensions. Lofts shall be not less than 5 feet (1524 mm) in any horizontal dimension. AQ105.1.3 Height effect on loft area. Portions of a loft with a sloping ceiling measuring less than 3 feet (914 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required area for the loft. Exception: Under gable roofs with a minimum slope of 6:12, portions of a loft with a sloping ceiling measuring less than 16 inches (406 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required area for the loft. AQ105.1.4 Minimum ceiling height. Lofts shall have a ceiling height of not less than 3 feet (914.4 mm). AQ105.1.4.4.1 Undersized lofts. Lofts having a ceiling height of less than 6 feet (1828.8 mm) for more than 50 percent of the required minimum area shall comply with both of the following: 1. All wall and ceiling of the dwelling unit shall be a minimum 1/2 inch gypsum board or other approved Class A finish, throughout the entire dwelling unit. 2. In addition to the loft smoke alarm required by AQ105.4, all other required smoke alarms within the dwelling unit shall be a photoelectric-type complying with R314. AQ105.1.5 Maximum loft size. The aggregate floor area of a loft shall not be greater than one-third of the floor area of the room or space in which they are located. AQ105.2 Loft access. The access to and primary egress from lofts shall be of any type described in Sections AQ105.2.1 through AQ105.2.4. All methods of loft access and egress shall be positively anchored to prevent displacement. AQ105.2.1 Stairways. Stairways accessing lofts shall comply with this code or with Sections AQ105.2.1.1 through AQ105.2.1.5. SUPP. 11 (1-2022) 5B-44 RESIDENTIAL BUILDING CODE § 5B-3-3 AQ105.2.1.1 Width. Stairways accessing a loft shall not be less than 17 inches (432 mm) in clear width at all points at or above the permitted handrail height. The minimum width below the handrail shall not be less than 20 inches (508 mm). AQ105.2.1.2 Headroom. The headroom in stairways accessing a loft shall not be less than 6 feet 2 inches (1880 mm) measured vertically from the sloped line connecting the tread nosing in the middle of the tread width. Exception: The headroom for landing platforms shall not be less than 4 feet 6 inches (1372 mm). AQ105.2.1.3 Treads and Risers. Risers for stairs accessing a loft shall be a minimum of 7 inches (178 mm) and a maximum of 12 inches (305 mm). Tread depth and riser height shall be calculated with the following formulas: Tread depth = 20 inches (508 mm) minus 4/3 riser height or Riser height = 15 inches (381 mm) minus 3/4 tread depth Exception: Landing platforms shall measure two treads deep and two risers tall. AQ105.2.1.4 Handrails. Handrails shall comply with Section R311.7.8. AQ105.2.1.5 Stairway guards. Guards at open sides of stairways shall comply with Section R312.1. AQ105.2.2 Ladders. Ladders accessing lofts shall comply with Sections AQ105.2.2.1 and AQ105.2.2.2. AQ105.2.2.1 Size and capacity. Ladders accessing lofts shall have 12 inches (305 mm) minimum rung width and 10 inches (254 mm) to 14 inch (356 mm) spacing between rungs. Ladders shall be capable of supporting a 300 pound (136 kg) load on any rung. Rung spacing shall be uniform within 3/8-inch (9.5 mm). The maximum height of a ladder shall be 8 feet (2438 mm). AQ105.2.2.2 Incline. Ladders shall be installed at 70 to 80 degrees from horizontal. 5B-45 SUPP. 11 (1-2022) AQ105.2.3 Alternating tread devices. Alternating tread devices accessing lofts 200 square feet or less shall comply with Sections R311.7.11.1 and R311.7.11.2. The clear width at and below the handrails shall be not less than 20 inches (508 mm). AQ105.2.4 Ships ladders. Ships ladders accessing lofts 200 square feet or less shall comply with Sections R311.7.12.1 and R311.7.12.2. The clear width at and below the handrails shall be not less than 20 inches (508 mm). AQ105.3 Loft guards. Loft guards shall be located along the open side(s) of lofts located more than 30 inches (762 mm) above the main floor. Loft guards shall be not less than 36 inches (914 mm) in height or one-half the clear height to the ceiling, whichever is less. Loft guards are not required at the loft accessing means connection to the loft. AQ105.4 Loft smoke alarms. Lofts shall be equipped with a minimum of one photoelectric-type smoke alarm complying with Section R314. AQ105.5 Loft location. Lofts shall not be located directly above a permanently installed cooking appliance. Permanently installed cooking appliances shall not be located within 12 inches (304.8 mm) horizontally of a loft open edge, measured to the vertical plane of the loft edge. SECTION AQ106 EMERGENCY ESCAPE AND RESCUE OPENINGS AQ106.1 General. Tiny houses shall meet the requirements of Section R310 for emergency escape and rescue openings. Exception: Egress roof access windows in lofts used as sleeping rooms shall be deemed to meet the requirements of Section R310 where installed with the bottom of their clear opening no more than 44 inches (1118 mm) above the loft floor provided the egress roof access window complies with the minimum opening area requirements of Section R310.2.1.” (2021, ord 21-61, sec 1.) 5B-3-3 SUPP. 11 (1-2022) 5B-46 RESIDENTIAL BUILDING CODE § 5B-3-21 Division 2. Appendix Added to the International Residential Code.