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In addition, the product adheres well to steel roofing panels, wood, concrete, polyurethane foam, and tar and gravel built up roofing. This product remains permanently flexible, even in below freezing temperatures, affording a watertight membrane that will not chalk or fade with continuous exposure to the elements. The coating is able to withstand hail as well as foot traffic from workmen servicing rooftop installations.
Solving a public health issue
A number of large North American cities, including Philadelphia, have become increasingly concerned about the number of heat-related deaths each summer, especially among the elderly. Two years ago, a Philadelphia non-profit organization, Energy Coordinating Agency Inc., began putting white coating on the roofs of older residents in low-income city neighbourhoods. They found that the coatings reduced the temperature inside these homes, making them safer for elderly residents. Now Philadelphia is considering a new building code mandating that flat or low-slope roofs have high solar reflectance.
 In most cases, this means coating them white. Chicago recently adopted a similar building code. Toronto recently introduced an Eco-Roof Incentive Program, designed to promote the use of cool roofs (white reflective) on its commercial, industrial and institutional buildings, and to help its business community take action on climate change.
Saving the planet one roof at a time
Nearly 17 per cent of all electricity consumed in North America is used to cool buildings. Coating black roofs white can help reduce that number by increasing energy efficiency. During a one-year study, scientists discovered that a building with a white acrylic roof coating consumed nearly 22 per cent less energy for air conditioning in the summer than one with an uncoated black roof. Surprisingly, the white coating also reduced energy demand by almost four per cent in the winter.
White roof coatings also contribute to a healthy environment by extending the lifespan of black roofs. Six per cent of waste material dumped in landfills consists of old roofing waste. White coatings help roofs last longer by reducing the drastic changes in temperature that cause roof wear and tear, and that benefits the environment by reducing the size of our landfills. The cost to coat an existing tar and gravel roof is less than half the cost of re-roofing.
Reflectance of typical Roof Materials
| Material Solar Reflectance (%) Roof Temperature |
27ºC Air Temperature |
| Safe-T-Plex White Elastomeric Coating* |
83.3% 28ºC |
| White membrane |
70%-80% 35º |
| White metal |
60%-70% 35º - 40º |
| Bright aluminum coating |
55% 40º - 46º |
| Premium white shingle |
35% 60º |
| Generic white shingle |
25% 66º |
| Light brown/gray shingle |
20% 68º |
| Dark red tile |
18%-33% 62º - 69º |
| Dark shingle |
8%-19% 68º - 75º |
| Black shingle or materials |
5% 77ºC |
Source: Exova Materials Testing, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, and the Florida Solar Energy Center
Benefits to solar energy systems
Solar panel efficiency -- the ability to convert sunlight into electricity -- is negatively affected by heat. Heat accumulated by a dark roof on a sunny day reflects up to the solar panels, reducing their efficiency by as much as 30 per cent. Prolonged exposure to this heat can actually damage the internal workings of the panels. The solution is simple -- coat the roof with white elastomeric coating.
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