TPO Replacement for Leaking EPDM Roof in Flagstaff, AZ

An aging EPDM roof at a FedEx shipping facility in Flagstaff, AZ was leaking and disrupting operations. The property owner chose an owner-funded replacement (no insurance claim) to stabilize the building envelope before peak season. Over three weeks, our roofing team delivered a new roofing system designed for durability in cold mountain conditions and around-the-clock logistics activity.

Project At-a-Glance

• Roof size: 135,000 sq ft (≈1,350 squares)
• Manufacturer/system: Carlisle TPO
• Insurer: None (owner-funded)
• City: Flagstaff, AZ

Challenge: Stop active leaks and keep a busy Flagstaff shipping hub moving in cold weather

The existing EPDM roof had reached the end of its service life, showing leaks that risked interior operations. Work needed to proceed during cold temperatures with attention to safety, staging, and city permitting in Flagstaff. The facility’s loading and sorting activity demanded clean, controlled phases to avoid downtime.

Solution: A durable, manufacturer-warrantied TPO system tailored for cold-weather performance

We removed the aged EPDM and kept the polyiso insulation in place, reusing the existing rock ballast to streamline cost and schedule. We installed a 115-mil Carlisle FleeceBack TPO field membrane as a ballasted system on the low-slope section of the main building, then applied 60-mil Carlisle TPO on parapet walls to complete a continuous waterproofing envelope. Critical details included new boot flashings at penetrations, scupper reseal, and reusing the metal wall cap to maintain edge integrity.

• Removal of existing EPDM to polyiso; salvage and reuse rock ballast for the new ballasted TPO system.
• Install Carlisle 115-mil FleeceBack TPO (field) and 60-mil TPO at parapets for a continuous system.
• Flash all penetrations with TPO boots; reseal exterior scuppers; reuse existing metal wall cap.
• Use Carlisle system components and chemistries (CAV-Grip adhesive, primers, cut-edge sealant, detail flashing, cleaner) for manufacturer compatibility.
• Add two-way TPO breather vents to help manage moisture vapor beneath the membrane.
• Three-week schedule coordinated around cold temps and City of Flagstaff permitting to keep the facility operational.

This roofing installation provided a clean, code-compliant transition from the leaking EPDM to a new roofing system backed by the manufacturer.

Result: A watertight, low-maintenance roof with long-term protection and peace of mind

The facility now has a robust Carlisle TPO system with a 20-year NDL manufacturer warranty and a 5-year workmanship warranty for added confidence. The manufacturer states the membrane is warrantied in ponding water conditions, defined as water that remains longer than 48 hours, supporting performance through Flagstaff’s freeze-thaw cycles. If the building is sold, the NDL warranty is transferable, preserving asset value. Operationally, the owner gained a cleaner roofscape, improved drainage paths at scuppers, and fewer leak-related interruptions—delivering both protection and day-to-day peace of mind.

Trust & Proof: Manufacturer-backed system and documented workmanship in Flagstaff

This project features a Carlisle TPO roofing system installed to manufacturer guidelines with compatible components throughout, supporting warranty integrity. The combination of a 20-year NDL and a 5-year labor warranty gives the property owner clear coverage for long-term service in Flagstaff.