What are the two parts of flashing around a masonry chimney?

The correct answer identifies the two essential components of flashing around a masonry chimney: base flashing and counter flashing.

Base flashing is installed at the base of the chimney, where it meets the roof, and is designed to direct water away from that critical junction. It plays a vital role in preventing water from penetrating the roof structure and causing leaks. This type of flashing is typically integrated beneath the roofing material to maintain a weather-tight seal.

Counter flashing, on the other hand, is positioned over the base flashing and is installed into the masonry of the chimney. Its purpose is to divert water away from the top edge of the chimney, effectively blocking any moisture that might run down the chimney from entering underneath the base flashing. The combination of these two types of flashing ensures that both elements work together to create a barrier against water intrusion, reinforcing the integrity and longevity of the chimney and the surrounding roofing system.

Understanding the role of both base and counter flashing is essential for proper chimney installation and waterproofing, making it crucial for carpenters and builders to be familiar with their function.