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The decision to coat a roof systems is usually made based on one or more general objectives:
- Extending maintenance and service life encompasses protecting against ultraviolet light and moisture, repairing leaks and cracks, extending service lives of underlying membranes and insulation by lowering average roof surface temperatures, reducing expansion and contraction stress by lowering peak temperatures, maintaining waterproofing properties, protecting roofs from severe weather (such as hail and ice storms), and treating and preventing corrosion of metal roof systems.
- Improving energy savings relates to cool roofing and tax credits associated with air conditioning costs, the size of HVAC units, insulation preservation, and reducing the roof’s life-cycle cost.
- Enhancing safety involves maintaining or upgrading a fire rating, as well as bonding loose and friable materials.
- Promoting environmental stewardship includes reducing landfill waste and limiting the effects of urban heat island.
These objectives have become part of an industry-wide movement aimed at saving energy and improving sustainability.
Longer roof-system life cycles reduce the energy required to tear off and transport failed systems to landfills, as well as the energy needed to manufacture new roofing materials, transport them to job sites and install them. In short, to maintain is to sustain.
Extending a roof system’s life cycle also means less downtime and no lost income during roof replacement. In contrast to re-roofing projects, roof-coating applications generally do not require a building shutdown.
Reducing solar heat gain also directly affects a building’s peak electricity requirements. Peak loads often form the basis of electricity prices because they establish a region’s energy-generating needs.
Some white reflective coatings can reflect 80 percent or more of the sun’s rays at installation. As a result, they reduce air conditioning costs. When used as part of an ongoing roof-maintenance program, managers typically can treat coatings as an expense, not a capital investment.
Finally, a cool roof can mean a smaller initial investment in air conditioning equipment when the equipment is included in the planning for a new roof.