Thru-Wall Flashing

Common causes include original installation defects, material degradation over time, thermal movement that tears the membrane, mortar droppings that block weep holes, and incompatible materials. On older buildings, the flashing material itself may have reached the end of its service life.

Flashing should be evaluated whenever interior water infiltration is reported at floor lines or window heads, when the building undergoes a masonry investigation, or when planning major masonry restoration work. An investigation can identify flashing failures before they cause significant interior damage.

Thru-wall flashing is a concealed membrane installed within a masonry wall at transitions, shelf angles, window heads, and parapets to intercept moisture and direct it back outside through weep holes. It is one of the most critical components in a masonry wall system for preventing water infiltration into the building interior.

Most building codes require thru-wall flashing at specific locations within masonry wall assemblies, including bases of walls, shelf angles, lintels, and parapets. Code requirements vary by jurisdiction, and our team is experienced with the code expectations across our service area.

Thru-wall flashing is a membrane installed within the masonry wall assembly to redirect water that enters the wall back to the exterior through weep holes. It fails when it is improperly installed, deteriorates with age, or becomes displaced by building movement, allowing water to bypass the drainage system entirely.

Interior water staining at floor lines, window heads, or shelf angle locations; efflorescence on the exterior face; saturated masonry below parapet caps; and recurring leaks that do not respond to tuckpointing or sealant replacement are all strong indicators of flashing failure.

Cost depends on the linear footage of flashing, the wall construction, the height and access requirements, and whether additional masonry repairs are needed during the process. We work with building owners to prioritize the most critical flashing locations and can phase the work over multiple periods to fit the budget. Contact us for a site visit.

We use stainless steel, copper, rubberized asphalt membranes, and other proven flashing materials selected based on the wall construction, exposure conditions, and project specifications. Material selection is discussed during the proposal process.

Yes. When a parapet is rebuilt, installing thru-wall flashing at the base of the rebuild is standard practice to prevent water from migrating into the wall cavity below. We also address cap flashing, coping, and counter-flashing connections to ensure the rebuilt parapet sheds water properly and protects the roof system.

Masonry is carefully removed in sections above the flashing line, the failed flashing is removed, new flashing membrane is installed with proper end dams and laps, and the masonry is rebuilt to match the existing wall. We self-perform all masonry restoration with our own crew.

Modern flashing materials, when correctly detailed and installed, can last the life of the wall system. We provide a 2-year written workmanship warranty, and material manufacturers provide their own separate warranties. Over 30 years of work, our warranty claims have been virtually non-existent.

When flashing fails, water that enters the wall cavity is no longer intercepted and redirected to weep holes. Instead, it migrates inward through the backup wall, causing interior staining, mold growth, damage to finishes, and deterioration of structural components over time.

Yes, flashing replacement is typically performed in manageable sections by removing courses of masonry above the flashing line, installing new flashing, and rebuilding. This staged approach allows the work to proceed without destabilizing the wall.