On built-up roofs, cement each felt sheet with how many pounds per square of asphalt or how many pounds per square of pitch?

On built-up roofs, cement each felt sheet with how many pounds per square of asphalt or how many pounds per square of pitch?

• A. 20 pounds per square of asphalt and 30 pounds per square of pitch
• B. 10 pounds per square of asphalt and 20 pounds per square of pitch
• C. 15 pounds per square of asphalt and 25 pounds per square of pitch
• D. 25 pounds per square of asphalt and 35 pounds per square of pitch

Answer: (A)

When you’re cementing felt sheets on a built-up roof, you’re bonding each layer to the deck with asphalt, and the amount you apply is specified per square (a square is 100 square feet). The standard practice distinguishes between flat/ordinary bonding and pitched (sloped) surfaces to ensure a reliable seal under different conditions. The bonding rate is 20 pounds of asphalt per square for general cementing, but on pitched roofs you need more adhesion to resist gravity, wind uplift, and potential runoff, so 30 pounds per square is used. This balance provides a strong, durable bond without unnecessary excess. So the correct approach is to use 20 pounds per square of asphalt for the standard bonding and 30 pounds per square for pitch, reflecting the differing needs of flat versus pitched surfaces.

When you’re cementing felt sheets on a built-up roof, you’re bonding each layer to the deck with asphalt, and the amount you apply is specified per square (a square is 100 square feet). The standard practice distinguishes between flat/ordinary bonding and pitched (sloped) surfaces to ensure a reliable seal under different conditions. The bonding rate is 20 pounds of asphalt per square for general cementing, but on pitched roofs you need more adhesion to resist gravity, wind uplift, and potential runoff, so 30 pounds per square is used. This balance provides a strong, durable bond without unnecessary excess. So the correct approach is to use 20 pounds per square of asphalt for the standard bonding and 30 pounds per square for pitch, reflecting the differing needs of flat versus pitched surfaces.