Parapet
CSI Division 07, Thermal and Moisture Protection
The short wall that extends above a roof's edge, capping where the roofing membrane and the building's exterior wall meet, and that has to be properly flashed and waterproofed since it's one of the most common places a roof actually leaks.
Why it matters
A parapet creates a transition between two different waterproofing systems, roof membrane and wall cladding, meeting at a vulnerable corner, which is exactly why parapet flashing details get so much attention in roofing design. A detail that looks minor on a drawing is often where a real roof leak ends up starting.
On a real project
A roofing crew installs flashing that wraps the parapet wall's cap and ties the roof membrane up and over it, creating a continuous waterproof transition at the corner where the roof and the parapet wall meet.
Who this matters most to
A Roofer pays particular attention to parapet flashing details, since this transition is one of the most common points of failure on an otherwise well-installed roof.
Where this goes wrong
A roofing crew installs the main roof membrane correctly but rushes the parapet flashing detail where it should wrap properly up and over the wall. A gap at that transition isn't noticed until water finds its way through during the first significant rain after installation.