Weep Vents

A weep hole is an opening left or installed to prevent water from accumulating behind a wall or within a wall. Weep holes should be large enough to allow for moisture flow and fill the open head joint. A weep hole made of the same material as the drainage mat provides a continuous flow from the wall to the exterior for any accumulated moisture. They should also provide a barrier to insect penetration into the wall cavity.

Weep hole vents must be flame resistant and UV stable as they are exposed to sunlight. In order to be less noticeable, the color of the material should match the mortar used on the project. According to the BIA, the recommended spacing of weep holes depends on the materials. In a unitized flashing system, weep holes can be as close as 6 inches apart and in traditional flashings as much as 24 inches from center to center. The use of tubes as a weep hole material is no longer recommended as they can easily clog.

Termination Bars

A termination bar is a piece of plastic or metal with holes punched in it at a predetermined space to allow it to be adhered to the substrate wall. When the only structural system was double wythe masonry, a piece of flashing was laid into the bed course of the backup CMU wall one course above the flashing level. A mason dropped down the flashing and curled it over the brick shelf. This method often required a team of masons to hold, roll, glue and place weeps. With the advent of alternative substrates as the back up wall system, the termination bar “caps” the flashing system and is placed horizontally on the vertical wall.

The choice of materials for a termination bar is often selected by the contractor or architect and is related to geographic preferences. Sixteen gauge stainless steel termination bars with mounting screws can be selected for their durability and compatibility with all substrates.

Drip Edges

Uniform drip edges are possible with a unitized flashing product as shown in this wall completed for the Hampton University Dining Hall. Photo courtesy of Mortar Net® USA, Ltd.

Drip edges are one of the most visible components of wall flashing. A drip edge is the overhanging component of the flashing, usually metal provided to control the direction of wind driven rainwater and moisture within the wall system. The crispness of a drip edge is controlled by its placement and the material used. Quality drip edge materials are a minimum of 26-gauge stainless steel, cold rolled copper, and materials coated with polyvinylidene fluoride. Drip edges are usually curved at the end with an approximately 30-degree hem to avoid sharp edges.