Counter Flashing and Mortar Reglets
Installing counterflashing inside the mortar reglets of a brick chimney or other roof protrusion is generally considered a better practice than caulking counterflashing to the side of the brick. Here are a few reasons why:
Watertight seal: When counterflashing is installed inside the mortar reglets, it creates a continuous, uninterrupted barrier against water infiltration. This helps to ensure that water is directed away from the chimney or protrusion and prevents leaks and damage to the roof and the interior of the building. Caulking counterflashing to the side of the brick, on the other hand, leaves gaps that water can seep through, potentially causing leaks and damage.
Durability: Installing counterflashing inside the mortar reglets is a more durable method of installation because it is embedded into the chimney or protrusion. Caulking is a less permanent solution because it is only applied to the surface of the brick and can dry out, crack, or peel over time. This can lead to the need for frequent repairs or replacements, which can be costly and time-consuming.
Aesthetics: Installing counterflashing inside the mortar reglets can provide a more seamless, cohesive appearance because it is hidden from view. Caulking counterflashing to the side of the brick can be visible and may not match the color or texture of the brick, which can be unsightly.
Overall, installing counterflashing inside the mortar reglets is a more effective and durable method of sealing the base of a chimney or roof protrusion. While caulking may be a quicker and easier solution, it is not as reliable in the long term and may require more maintenance and repairs.