Which statement correctly describes the cementing weights used for built-up roofs?

Which statement correctly describes the cementing weights used for built-up roofs?

• 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)

In built-up roofing, cementing weights provide the downward pressure that helps press the felt into the hot bitumen as each ply is laid, ensuring full contact and proper adhesion while the asphalt or pitch cures. The standard practice is to use 20 pounds per square for asphalt and 30 pounds per square for pitch, per 100-square-foot area. A square equals 100 square feet, so these values are about 0.2 psf for asphalt and 0.3 psf for pitch. Using these weights helps prevent air pockets and movement, giving a solid bond between layers. Other weight options don’t match the typical BUR method and could lead to under- or over-pressing, compromising adhesion or causing damage.

In built-up roofing, cementing weights provide the downward pressure that helps press the felt into the hot bitumen as each ply is laid, ensuring full contact and proper adhesion while the asphalt or pitch cures. The standard practice is to use 20 pounds per square for asphalt and 30 pounds per square for pitch, per 100-square-foot area. A square equals 100 square feet, so these values are about 0.2 psf for asphalt and 0.3 psf for pitch. Using these weights helps prevent air pockets and movement, giving a solid bond between layers. Other weight options don’t match the typical BUR method and could lead to under- or over-pressing, compromising adhesion or causing damage.