(a) Except as specified in subsection (b) of this section, materials for indoor floor, wall, and ceiling surfaces under conditions of normal use shall be:

1. (1) Smooth, durable, and easily cleanable for areas where retail food establishment operations are conducted;
2. (2) Closely woven and easily cleanable carpet for carpeted areas; and
3. (3) Nonabsorbent for areas subject to moisture such as food preparation areas, walk-in refrigerators, warewashing areas, toilet rooms, mobile food establishment servicing areas, and areas subject to flushing or spray cleaning methods.

(b) In a temporary food establishment:

1. (1) If graded to drain, a floor may be concrete, machine-laid asphalt, or dirt or gravel if it is covered with mats, removable platforms, duckboards, or other suitable approved materials that are effectively treated to control dust and mud; and
2. (2) Walls and ceilings may be constructed of a material that protects the interior from the weather and windblown dust and debris.