What is parapetin construction?

When the IBC requires a fire parapet, it generally must extend at least 30 in above the point where the roof surface meets the wall. For a parapet to serve as fall protection under OSHA rules it needs to be at least 39 in above the walking surface, which is why 42 in parapets are common on buildings with rooftop equipment. Outside those triggers the height is a design choice, so always pull it from the wall sections instead of assuming.

The field membrane turns up the inside face of the parapet as base flashing, typically a minimum of 8 in above the finished roof and often running to the top of short parapets. It is secured with a termination bar or carried over the wall, then protected by metal coping set over a continuous cleat and wood blocking. Tapered insulation can change the flashing height around the perimeter, and every scupper through the parapet is a flashed penetration that adds labor.

A parapet is exposed to weather on the outside face, the inside face, and the top, and unlike the wall below it has no conditioned space behind it helping it dry. The usual failure points are open coping joints, cracked mortar, saturated masonry, and a failed base flashing termination. On restoration estimates, carry repointing or rebuild quantities in sf plus new coping in lf rather than assuming a sealant fix.