Commercial TPO Roof Overlay in Flagstaff, AZ

A regional commercial property in Flagstaff, AZ required a low-disruption roofing installation to address an aging built-up roof (BUR) with active leaks and areas of ponding. The owner selected a new single-ply TPO roofing system installed as an overlay to restore watertight performance without a full tear-off.

Project At-a-Glance

• City: Flagstaff, Arizona
• Property type: Commercial building
• Roof size: 325 squares (~32,500 sq ft)
• Membrane: Carlisle 60-mil TPO (white)
• Separation layer: 1/2″ fan-fold EPS
• Attachment: Mechanically fastened
• Warranty: Carlisle 20-year NDL
• Insurance: None (owner-funded)

Challenge: Aging BUR, active leaks, and monsoon-season weather

The existing BUR on this Flagstaff property had reached the end of its service life, showing active leaks and water that tended to pool after storms. The project coincided with rainy periods, so the crew needed to keep the roof watertight at the end of every day while minimizing disruption to daily operations.

Solution: Mechanically fastened TPO overlay with daily watertight tie-ins

To resolve the issues quickly and cost-effectively, the team installed a Carlisle 60-mil TPO roofing system over a 1/2″ fan-fold EPS separation layer using a mechanically fastened attachment. This approach provided a smooth substrate, strong uplift resistance, and a bright, reflective surface—an ideal new roofing system for Flagstaff conditions from a trusted provider of commercial roofing services.

• Targeted removal of wet, compromised surface materials where needed, followed by thorough substrate preparation.
• Installation of 1/2″ fan-fold EPS to create a uniform surface and support membrane performance.
• Mechanically fastened 60-mil Carlisle TPO with manufacturer-approved fasteners, seams, and edge details.
• Daily temporary tie-ins and end-of-day waterproofing to maintain a watertight condition despite intermittent rain.
• Flashing of penetrations and terminations per manufacturer guidelines, followed by detailed QA for warranty submission.

Result: Watertight, brighter, and ready for Flagstaff’s seasons

The TPO overlay stopped active leaks, improved surface conditions for better drainage, and delivered a clean, reflective roof that supports long-term durability. The building owner now has peace of mind heading into Flagstaff’s wet and snowy seasons, backed by a 20-year manufacturer NDL warranty and a professional roofing installation built to last.

Trust & Proof: Manufacturer-backed system and documented specs

This commercial roofing installation follows Carlisle’s published standards and is supported by a 20-year NDL warranty for long-term confidence. System components—including 60-mil Carlisle TPO, mechanically fastened over 1/2″ fan-fold EPS across approximately 32,500 sq ft—are documented and align with best practices for commercial roofing services in Flagstaff, AZ.