Finish TradesQuestion 422 of 700
In a tub or shower area that will receive tile, which type of gypsum panel product is UNSUITABLE as the tile backing directly exposed to wet conditions?
a.Standard (regular) gypsum wallboard
b.Cement board
c.Glass-mat water-resistant backer panel
d.Fiber-cement backer board
Explanation
Standard gypsum wallboard is not acceptable as a tile backer in direct wet areas because its paper and core deteriorate with moisture. Cement board, glass-mat water-resistant backer, and fiber-cement backer are all manufactured to tolerate the wet exposure behind tub and shower tile.
Law Reference: 2025 CA Residential Code §R702.4Practice all 700 questions free — no signup required.
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