Richard K. Olson RSI Contributing Columnist

With the "green build" and "sustainable" branding machine ramping up around the world, there are still many questions regarding how this universal movement will impact our business at home and how it will relate to the true life-cycle costs of our building projects. While most of these programs will be based upon color reflectivity, it really raises the question of long-term performance of these new systems.

While the research and testing of color reflectivity standards are, for the most part, complete, the long-term aging data is still a few years away. Numerous new products are about to be marketed as providing great performance for energy reduction, but real-life application over time is not available. One significant measurement for determining whether a roof is truly cool will be in the re-evaluation of life-cycle costing, which will need to be revisited for many roofing materials now entering the marketplace. Concrete and clay tiles, however, will be one of the shining stars for designers to use. We already know their performance.

Tile improves with age

Concrete and clay tile roofs have traditionally been considered a premium product with a premium cost. While most tile roofs on a first-install basis will be two times to three times the cost of the basic asphalt shingle roof, the actual life-cycle cost of a tile roof is significantly lower and usually half the yearly cost of the asphalt shingle. The extremely long life of tile and the almost negligible annual maintenance costs have made it the preferred roofing material in many other areas of the world.

The new green-build and cool-roof movements will also introduce the use of expensive, special iron oxide pigments to color the asphalt shingle granules. This will not only help close the gap on initial installed costs, it will greatly improve the cost benefit for using tile over asphalt shingles or metal. Since the long-term life of such coloring systems is really not defined or known, building professionals will need to consider the impact of the unknown on the annual roofing costs. In some cases, special coatings will need to be reapplied after seven years to 10 years based on laboratory testing (and may prove shorter in real life).

In addition, the ability for the tile roofs to provide natural ventilation and be applied in a direct deck, batten, and even counter-batten fashion to increase the available airflow will allow the traditional tiles to exceed the various program requirements. This will provide the customer the satisfaction of knowing that a tile roof will continue to provide the long-term performance we have seen for centuries around the world. The net results may show that concrete and clay tiles can in fact be about 10 percent to 20 percent of the annual life-cycle costs found with other cool roof-rated roofing materials, making it the preferred choice of roofing in the United States.