Flat roofs, especially on commercial and restaurant buildings, rely on a streamlined design to remain leak-free and durable. But hidden within that simplicity are two of the most vulnerable components of any low-slope roof system: seams and penetrations.
While manufacturers have addressed seam weaknesses by creating wide rolls of membrane, sometimes over ten feet across, penetrations remain an unavoidable design element. These are any structures that interrupt the membrane layer and pierce through the insulation and roof deck. Soil stacks, gas lines, heat vents, plumbing stacks, and rooftop HVAC units (RTUs) all fall under this category. And each one represents a potential entry point for water.
Large rooftop units are typically mounted on curbs that are integrated into the roofing system and flashed in with care. But smaller penetrations aren’t always so fortunate. To seal them, manufacturers supply prefabricated solutions like pipe boots and pitch pockets. Pipe boots are clamped and sealed at the top, while pitch pockets are filled entirely with sealant to create a watertight barrier. When these items are installed properly and maintained regularly, they function as intended. But when neglected, they quickly become problem points.
The key issue is that many owners underestimate how frequently these flashings degrade. UV exposure, temperature swings, and movement of the penetrated object (like a swaying pipe) all accelerate wear and tear. Once a flashing begins to fail, water has a direct path into the roof system and in many cases, into the interior of the building.
At RoofingSource, we routinely see this in the field. It’s common for sealants to shrink as they age to find pitch pockets that have dried out or cracked open, or pipe boots that have lost their seal due to age or movement. These issues often go undetected until the damage is already done.
In addition to routine wear, we also encounter installations that were never correct in the first place. Whether due to rushed construction timelines or a lack of oversight, poorly flashed penetrations are a leading cause of early roof failure. And when penetrations are modified or abandoned without being properly removed and patched especially during major remodels or equipment replacements roof warranties can be voided altogether.
To prevent these issues, manufacturers require all penetrations to be installed to spec and kept in good condition. This includes removing any obsolete penetrations that are no longer in use. Doing so isn’t just about maintaining the roof, it's about preserving the warranty and protecting the business underneath.
Our RoofCare program is a critical safeguard for your business. By streamlining both proactive and reactive repairs, it creates a consistent, repeatable system for managing rooftop issues across every location making it essential to keeping your business running. With regular inspections that specifically check the condition of flashings, pitch pockets, and other detail items, these essential checkups catch early signs of failure before they become full-blown leaks.
For owners looking to protect their investment and ensure compliance with manufacturer requirements, consistent inspection and maintenance of penetrations is non-negotiable. In addition to causing roof leaks, failing penetrations can also damage insulation and decking, leading to avoidable and costly repairs.
The bottom line, penetrations may be small, but their impact is significant. Left unchecked, they’re a silent killer of flat roofs. But with the right planning, installation, and follow-through, they don’t have to be.
Need expert eyes on your roof? Contact RoofingSource below or call (833) 247-7663 today to schedule a roof assessment.
Written by
Benjamin Burdick
Field Support Representative
benjamin.burdick@roofingsource.com
