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Case Studies

GacoFlex S20 Silicone Over Hail-Damaged Single-Ply & Acrylic-Coated Foam Roof – Costco Corporation (AZ)

Case History GacoFlex S20 Hail Damaged Single Ply Acrylic Foam Restored Costco AZ Photo1


During the summer of 2011, the 152,000+ sq. ft. roof of the Costco Warehouse in Scottsdale, AZ sustained severe hail damage which voided the manufacturer’s warranty on their roof. The Costco Wholesale Corporation is self-insured, so they could not turn to an insurance company to pay for the repairs that were needed. The company wanted the lowest cost, best performing, longest lasting and quickest installed solution possible – a tall order for any roofing project.

Costco put the project out to bid and was considering a variety of solutions.


Progressive Roofing provided a solution that was far superior to any acrylic coating on the market, and offered a 20 year warranty. GacoFlex S2000 Solvent-Free 100% Silicone Roof Coating features FM approval, has a highly reflective, glossy finish that can reduce cooling costs, and will endure permanent ponding water without softening.

All of Costco’s criteria were met. A year and a half later, the roof is in excellent condition and with a 20 year warranty Costco can rest assured it will stay that way.

Unique Characteristics:

Repairs were needed on two types of roofing surfaces, and the work had to be completed during business hours at this very busy warehouse–without interrupting business or inconveniencing customers with strong odors. The entire project took about one month to complete, and during that time Costco did not receive a single customer complaint.


The existing hail-damaged roof was comprised of approximately 145,000 sq. ft. of foam coated with acrylic, and 7,500 sq. ft. of single-ply membrane. The entire roof surface was thoroughly cleaned with GacoFlex D09 Biodegradable Cleaner, and then a single coat of GacoFlex S2000 Solvent-Free 100% Silicone was applied at a rate of 2 gallons per 100 sq. ft. While a typical specification calls for use of E5320 2-Part Epoxy Primer/Filler, on this project no primer was required because GacoFlex S2000 will bond to a well-prepared, chalk-free, acrylic coated substrate.

Location: Scottsdale, AZ
Specification: RC-HD-GF20 (GacoFlex S20 Silicone)
Product Type: Hail-Damaged Single-Ply & Acrylic-Coated Foam Roof Restoration
Contractor: Progressive Roofing
Problem Solved: Existing roof was severely hail damaged.
Customer: Costco Corporation