By William A. Kirn, RRC Technical Director National Coatings Corporation
Apple Computer has been widely acknowledged as a leader and innovator in personal computing. For all their forward thinking and creativity, they faced a problem all too familiar to other more mundane industries; “How to prolong the life of their degraded roof?” The aged built up roof (skin) on their 28,500 ft2 facility in Cupertino CA leaked and was in poor condition. Moreover, its dark color contributed to very high air conditioning bills. There were also numerous leaks at privacy/wind screen supports and the roof had poor drainage.
Numerous roofing options were considered, each promising to solve their problems, but most at a very high cost. After a critical review of the roof needs and the options proposed by several contractors, Apple chose the National Coatings Corporation AcryShieldR Roof Restoration System.
Since the roof was in generally sound mechanical condition, the roof restoration system took advantage of the existing life of the roof, allowing the roof to be kept in place and without the need for an expensive tear off. Leaks around the many screen supports were eliminated using an innovative sprayed polyurethane foam sealing system. Additional slope was created and ponded areas were eliminated using the SPF material. Then the entire roof was coated with a primer coat of AcryShield acrylic roof coating. While the coating was still wet, polyester reinforcing mesh scrim was embedded into the coating. After drying, a second coat of AcryShield roof coating was applied.
This system created a monolithic seamless fully adhered, reinforced membrane to the existing roof. Moreover, the white color with its high solar reflectance and emittance dramatically reduced the cooling load on the building, thereby reducing air conditioning energy costs.
To the facility managers at Apple Computer, this alternative accomplished several key things:
- The roof was restored without costly and disruptive tear off.
- The leaks were eliminated and additional slope was created.
- The AcryShield system provided an additional 30 dry mils of coating plus increased tensile strength from the polyester reinforcing scrim.
- The roof is easily maintainable, as it can be recoated as needed, usually every 8-12 years.
- The white color reduced the cooling load and related air conditioning costs on the building
- This option has the lowest life cycle cost of any reroofing option.