What is the preferred type of asphalt for slopes greater than 1:12 in built-up membranes?

What is the preferred type of asphalt for slopes greater than 1:12 in built-up membranes?

• A. Type I Asphalt
• B. Type II Asphalt
• C. Type III Asphalt
• D. Type IV Asphalt

Answer: (C)

The preferred type of asphalt for slopes greater than 1:12 in built-up membranes is Type III Asphalt. This choice is correct because Type III Asphalt has a higher viscosity and melting point compared to other types, making it more suitable for steep slopes. Its robust properties help ensure better performance in various weather conditions and support the structural integrity of the built-up roofing system. Using Type III Asphalt on steeper slopes minimizes the risk of flow or run-off of the bitumen under elevated temperatures, maintaining the adhesion and continuity of the roofing membrane. This is particularly important in ensuring that the roofing system effectively adheres to substrates and provides the necessary waterproofing. In contrast, other types of asphalt, like Type I and Type II, may not provide the same level of performance and stability on steep slopes due to their lower viscosity. This can lead to potential issues such as slippage or inadequate bonding, which can compromise the roofing system's effectiveness over time. Type IV Asphalt tends to be used for specialized applications that do not align with the requirements for built-up roofing on steep slopes.

The preferred type of asphalt for slopes greater than 1:12 in built-up membranes is Type III Asphalt. This choice is correct because Type III Asphalt has a higher viscosity and melting point compared to other types, making it more suitable for steep slopes. Its robust properties help ensure better performance in various weather conditions and support the structural integrity of the built-up roofing system.

Using Type III Asphalt on steeper slopes minimizes the risk of flow or run-off of the bitumen under elevated temperatures, maintaining the adhesion and continuity of the roofing membrane. This is particularly important in ensuring that the roofing system effectively adheres to substrates and provides the necessary waterproofing.

In contrast, other types of asphalt, like Type I and Type II, may not provide the same level of performance and stability on steep slopes due to their lower viscosity. This can lead to potential issues such as slippage or inadequate bonding, which can compromise the roofing system's effectiveness over time. Type IV Asphalt tends to be used for specialized applications that do not align with the requirements for built-up roofing on steep slopes.