Date
Inquiry
Can projects meet the backer board requirement in ID 2.1 part (c) through the use of paper-faced gypsum that meets the ASTM mold-resistant standard?
Ruling
The use of paper-faced backer board that meets the mold resistant standard ASTM D 3273 with a score of 10 is acceptable for exposed walls and behind fiberglass surrounds. Behind tile, nonpaper-faced backer board is still required in all cases.
Updated 10/1/13 for rating system applicability.
Internationally Applicable
On
Campus Applicable
Off