When a lead flashing for a vent stack is used, what is the minimum weight per square foot of the lead?

The minimum weight of lead flashing used for a vent stack is specified as 2 1/2 pounds per square foot. This weight is essential to ensure that the flashing is heavy enough to resist wind uplift and provide adequate sealing over time. The use of lead flashing is common in roofing applications because of its durability and malleability, allowing it to be shaped to fit snugly around irregular surfaces and penetrations such as vent stacks.

Choosing a weight of 2 1/2 pounds per square foot strikes a balance between providing enough mass to stay in place under various weather conditions while also being manageable for installation purposes. A heavier flashing could be more challenging to work with, whereas lighter options may not offer sufficient protection, leading to potential leaks or failures in the flashing system.

In roofing standards, the specified weight is based on industry best practices and research into material performance, ensuring long-term reliability in sealing and weatherproofing applications.