R702.4.2

Section R702.4.2 is titled 'Backer boards' and covers the requirements for ceramic tile backer board in tub and shower areas. A cross-reference to a table in this code which lists allowable backer board materials for ceramic tile in tub and shower areas, and the requirement to install the backer board in accordance with the manufacturer's installation instructions is established. The purpose of this section is to prevent water from penetrating the wall and to provide a resilient support for ceramic tile. Note that water-resistant gypsum backing board in conformance with ASTM C1396 is not included in the table.

The model shows a section of a bathroom with the ceramic tile backer board installed in the tub area highlighted.