Ben Franklin conducted the first reflectivity test in the 1760s. He took different colored swatches of fabric - from dark colored to light colored - and placed them in the Philadelphia snow. As the sun beat down, Franklin noted that the snow melted around the dark colored fabric prior to the snow melting around lighter colors.

Thermoplastic olefins (TPOs) are a blend of thermoplastics and elastomers. The chemical formulation consists of a thermoplastic base - polypropylene (PP) or polyethylene (PE) - and an elastomeric base - the ethylene-propylene rubber polymer of ethylene propylene diene terpolymer rubber (EPDM).

Slate tiles are one of the oldest types of steep-slope roof coverings in the United States. Their application dates back to colonial times. In recent decades, there has been a decrease in slate applications, due in large part to shortages in raw materials and a lack of skilled craftsman.

The most critical point of the roof assembly is the roof edge. This juncture is the most susceptible to wind uplift failures and moisture infiltration. The majority of roof damage created by high-velocity winds is initiated at the perimeter or corners of the building and infiltrates throughout the field of the system.

When properly applied, coatings can provide significant advantages to a roof system. Coatings have been documented to expand the service life of existing roofs, improve a building’s energy efficiency, resist degradation from chemicals and ultraviolet radiation and eliminate the formation of small cracks associated with these degenerative conditions. Improper coating application leads to premature coating failures, which could lead to the demise of the roof system.

Recent technological advances have increased the acceptance of composite shingles in steep-slope roof applications. The increase in popularity can be attributed to the variety of styles and colors that are now available for these types of materials. The styles available include those that mimic the look of traditional three-tab shingles, wood shake shingles, slate shingles, metal and thermoplastics.

This year marks my 20th year in the roofing industry. In this time span, I have seen many significant changes in all sectors of the industry: contracting, manufacturing and consulting. As we close out 2007, I thought I would take a moment to reflect on some of these changes and provide a technical perspective on how these changes will affect the future of the industry.

SPF systems provide many advantages on low-slope roof systems. The primary advantage is that the material has a high thermal resistance value that increases per unit thickness. The application method is seamless, and with proper maintenance the system can provide a long-term life cycle in the proper environments. The long-term success of the system is dependent on the SPF coating.

Aggregate surfacing has been applied to built-up roof systems for over a century. The aggregate, which typically consists of gravel, crushed rock or blast-furnace slag, is set in a uniform

Some codes have already been altered to reflect the need for increased attachment methods in the aftermath of storms over the past few years. One of the codes altered involves the type of metal fabricated for use at the roof perimeter.