How many sheets of 4' x 8' x 1/2" drywall are needed for a room 10' x 15' with an 8-foot ceiling?

How many sheets of 4' x 8' x 1/2" drywall are needed for a room 10' x 15' with an 8-foot ceiling?

• A. 16 sheets
• B. 18 sheets
• C. 20 sheets
• D. 22 sheets

Answer: (B)

Start with the total area to be covered, including both the walls and the ceiling. The room’s walls make a perimeter of 2(10 + 15) = 50 ft, and with an 8 ft ceiling the wall area is 50 × 8 = 400 sq ft. The ceiling area is 10 × 15 = 150 sq ft. Combined, that’s 400 + 150 = 550 sq ft.

Each sheet of drywall covers 4 ft by 8 ft, or 32 sq ft. Dividing the total area by sheet coverage gives 550 / 32 = 17.1875, which means you need to round up to the next whole sheet. Therefore, 18 sheets are required.