That simple marking told a big story.

Last week, after the snow and ice finally cleared here in Dayton, Cotterman & Company Inc. completed a roof evaluation on a large warehouse facility that had recently started experiencing leaks.


As part of the inspection, a date stamp was located on the membrane: DL ’99.


That simple marking told a big story.


The building is protected by a Duro-Last PVC roofing system that was installed in 1999. After 25 years of service, the system has performed well — a testament to proper installation, maintenance, and the long-term durability of PVC roofing systems in commercial applications.


However, even well-performing systems eventually reach the end of their service life. With leaks beginning to show and the roof now at the 25-year mark, the timing makes sense to begin planning for replacement rather than continuing reactive repairs.


Cotterman & Company Inc. has provided reroof options so the customer can evaluate what best fits their long-term goals and budget. A key part of the discussion is warranty coverage. Once a new roofing system is installed, the facility can secure:

  • 20-year
  • 25-year
  • 30-year


Watertight material and labor manufacturer warranties — helping protect their investment for decades to come.


Finding a date stamp during an evaluation may seem like a small detail, but it provides valuable insight. It helps establish system age, guide realistic expectations, and support proactive planning instead of emergency decision-making.


If you manage or own a commercial facility and are unsure of your roof’s age or condition, a professional evaluation can provide clarity — and help you plan ahead before minor leaks turn into major disruptions.

Overhead view of a commercial building rooftop with multiple curved metal structures and flat rooftops.

Date stamp was located on the membrane: DL ’99.

White flat roof with vents and pipes.

View of the roof that's over 25 years old.

Red and gold logo for Cotterman & Company, Inc., celebrating 48 years of excellence, 1978-2026.

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January 9, 2026
After severe storms rolled through the area, our Service Department was called to a local hospital to investigate new roof leaks. Cotterman & Company responded quickly and delivered solutions that protected critical facilities with no shutdowns, no delays, and no compromises.
December 19, 2025
We want to take this opportunity to thank our valued customers for a wonderful year. Your trust and support have been the foundation of our success, and we’re truly grateful. We look forward to continuing to serve you with high-quality roofing solutions in 2026 and beyond!
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