What type of gypsum board is used on a curved wall?

• A. 54 x 12 x 1/4 type x
• B. 54 x 8 x 1/2 type x
• C. 4 x 8 x 5/8 MR board
• D. 4 x 8 x 1/4 flexboard

Answer: (D)

Curved walls need a gypsum board that can bend without cracking. Flexible gypsum board, or flexboard, is made thin—about 1/4 inch thick—so it can be curved to follow the wall’s shape. The 4x8 sheet size is common for this type, making it practical to install around curves with manageable seams. Thicker, standard boards (like 1/2 inch or 5/8 inch) are rigid and won’t hug a curved surface without gaps or cracks, and moisture- or fire-rated boards don’t address the flexibility needed for curvature. So the material used on a curved wall is flexible gypsum board.