112.5 concrete block units per 100 square feet of wall area. Approximately how many concrete block units (including the header blocks) will be required for the stem wall between the two bay areas on the north side of the house?

112.5 concrete block units per 100 square feet of wall area. Approximately how many concrete block units (including the header blocks) will be required for the stem wall between the two bay areas on the north side of the house?

• A. 96 Blocks
• B. 128 Blocks
• C. 150 Blocks
• D. 180 Blocks

Answer: (B)

The key idea is to convert wall area into the number of concrete blocks using the given coverage rate. If a wall area is 100 square feet, you would need 112.5 blocks; that’s 1.125 blocks per square foot. To estimate for the stem wall, multiply the wall area by 1.125. If the stem wall area between the two bay areas on the north side is about 114 square feet, then blocks needed ≈ 114 × 1.125 ≈ 128 blocks. The rate already accounts for header blocks, so no extra additions are needed for headers. Therefore, about 128 blocks are required.

The key idea is to convert wall area into the number of concrete blocks using the given coverage rate. If a wall area is 100 square feet, you would need 112.5 blocks; that’s 1.125 blocks per square foot. To estimate for the stem wall, multiply the wall area by 1.125. If the stem wall area between the two bay areas on the north side is about 114 square feet, then blocks needed ≈ 114 × 1.125 ≈ 128 blocks. The rate already accounts for header blocks, so no extra additions are needed for headers. Therefore, about 128 blocks are required.