Inspecting Parapet Walls

A parapet is a low wall around the perimeter of a low-slope roof. It functions as an integrated system of components that collectively manage water infiltration and protect the building envelope. To learn more about inspecting parapet walls and low-slope roof systems, take the self-paced Inspecting Commercial Low-Slope Roofs Online Course and earn your certificate upon completion.

The parapet wall shown in the video is a 10-foot concrete parapet from a 12-story office building inspection. The same principles applied throughout a commercial property inspection, plumb, level, square, and straight, apply equally to parapet inspections and should be evaluated around the entire perimeter of the building. Inspectors should also look for irregularities, such as:

• Loose, unsealed, rusted, defective fasteners, or deteriorated coping
• Improperly installed or damaged counterflashing that may allow water intrusion
• Loose base flashing or termination bars securing the roof membrane

Parapet Wall Components

Coping / Cap Flashing

Coping, also referred to as cap flashing, is the protective covering installed on the very top of the parapet wall. It is designed to shed water away from the masonry below and is typically wider than the wall itself, with a sloped surface to direct water off to the sides. Without properly sealed coping, water penetrates directly into the wall, leading to deterioration over time.

Counterflashing Trim

Counterflashing trim is installed along the wall above the flashing assembly where the wall surface meets the roofing components. It helps intercept water running down the face of the wall and directs it outward over the flashing below, preventing moisture from traveling behind the wall cladding or flashing system. This trim helps protect the transition between the vertical wall assembly and the components below. Counterflashing trim components are sometimes also referred to as Z-flashing.

Base Flashing and Termination Bar

At the base of the parapet wall, where the wall meets the roof surface, base flashing and a termination bar work together to secure the roof membrane to the wall. The membrane extends up the wall and is mechanically fastened with a termination bar. A sealant bead is typically applied along the top edge of the bar to prevent water from traveling behind the flashing and into the roof assembly. Failure at this transition is one of the most common sources of water intrusion in commercial roofing systems.

Electrical Receptacles

Parapet walls on commercial buildings may include electrical receptacles that serve rooftop or exterior building systems. These receptacles are exposed to outdoor conditions and should be evaluated for weather protection and accessible GFCI protection. If a GFCI protected receptacle is present but the trip point is not readily accessible, this should be noted in the inspection report.

Key Takeaway

Inspect parapet walls as a complete assembly. The coping, flashing components, and roof to wall termination work together to manage water at the roof edge. Deficiencies in these components, including the coping, counterflashing trim, and termination bar, can allow water intrusion into the roof system, wall assembly, or building interior.

During the preliminary walk-through, assess the exterior walls near the top of the building and the interior ceilings and walls on the top story for signs of moisture intrusion. Note any areas of concern so you can examine the corresponding parapet wall, flashing, and roof membrane during the roof inspection.

Learn more about inspecting parapet walls and low-slope roof membranes in the Inspecting Commercial Low-Slope Roofs Online Online Course. Included with CCPIA^® All-Access Membership.