(a) If the used manufactured home is installed according to the state's generic standards and the space under the home is to be enclosed with skirting and/or other materials provided by the retailer and/or installer, the enclosure must meet the following requirements:
  (1) At least one access opening that does not require the use of tools to gain access shall not be less than 18 inches in any dimension and not less than three square feet in area shall be provided by the installer. The access opening shall be located so as to enable, to the extent reasonably possible, the visual inspection of water supply and sewer drain connections.
  (2) If a clothes dryer exhaust duct, air conditioning condensation drain, or combustion air inlet is present, the installer must pass it through the skirting to the outside. All air conditioning condensation lines must be installed in such manner that prevents ponding within 5 feet of the foundation.
  (3) Crawl space ventilation must be provided at the rate of minimum 1 square foot of net free area, for every 150 square feet of floor area.
  (4) At least six openings shall be provided, one at each end of the home and two on each side of the home. There must be a ventilation within 3 feet of each corner. The openings shall be screened or otherwise covered to prevent entrance of rodents (note: screening will reduce net free area). For example, a 16'x76' single section home has 1216 square feet of floor area. This 1216 square feet divided by 150 equals 8.1 square feet or 1166 square inches of net free area crawl space ventilation.
(b) The generic ground vapor control measure shall consist of a ground vapor retarder that is minimum 6 mil polyethylene sheeting or its equivalent, installed so that the area under the home is covered with sheeting and overlapped approximately 12 inches at all joints. Any tear larger than 18 inches long or wide must be taped using a material appropriate for the sheeting used. The laps should be weighted down to prevent movement. Any small tears and/or voids around construction (footings, anchor heads, etc.) are acceptable.

Source Note: The provisions of this §80.22 adopted to be effective January 29, 2008, 32 TexReg 8790; amended to be effective July 21, 2009, 34 TexReg 3254