Asphalt has proved to be one of nature’s most useful and abundant materials since its discovery more than 5,000 years ago. This naturally occurring part of the environment is designated as part of the “bottom” of petroleum distillation and has been a popular roofing product since its introduction.
Whether you’re a longtime roofing professional or you’ve just had roofing added to your FM duties, there’s no time like the present to get up to speed on all things asphalt. Were you aware of these four asphalt facts?
1) It’s a component in many roofing systems.
As a soft material, it can be melted in the field, providing a high degree of waterproofing and retaining aggregate surfacings. The term “built-up-roofing” defines application of alternating layers of asphalt and sheet reinforcements.
Factory-applied asphalt can impregnate (saturate) organic or glass-fiber sheet reinforcements, and be used as underlayments for shingle-roof systems as well. Factory-applied mineral or ceramic roofing granules are solar-reflective and esthetically pleasing, and are used on both asphalt shingles and roll goods (cap sheets), on the top.
Modern applications blend polymeric materials such as atactic polypropylene and styrene butadiene styrene (APP and SBS) with selected asphalts to meet field conditions. The flexibility and toughness of MB blends make them useful for not only the membrane but for flashings as well.
Asphalt is also readily dissolved in petroleum solvents to form “cut-backs” as primers and roof coatings. It can be dispersed (emulsified) in water and clay particulates to make fire-resistive coatings.
2) It can be recycled – sometimes on-site.
The roofing industry has been recycling for more than a century. Original reinforcements were based upon collecting and shredding rags, hence the term “rag felt.” As clothing evolved into synthetic fibers which were not suitable for roofing, organic fibers such as newsprint and sawdust were successfully substituted and are still a viable roofing option. Both shingle underlayments (#15 felt) and asphalt shingles based upon either organic felt or glass fiber can be recycled.
Asphalt paving can be recycled in situ. Existing paving is ground up, blended with fresh hot asphalt, and replaced, allowing the road to be placed back in service in minutes.
3) Low-emitting asphalts exist.
Roofing asphalts have been engineered to be low-fuming, an important consideration when a building is occupied while reroofing takes place. Modified bituminous roof membranes that incorporate atactic polypropylene offer greater flexibility and ductility than unmodified membranes.
4) Trade associations can teach you more.
The Asphalt Roofing Manufacturing Association (ARMA) is celebrating its 100th anniversary in 2015. This organization has brought the industry together under the common goal of championing asphalt roofing and it is estimated that almost 95% of the nation’s manufacturers of bituminous-based roofing products are members. To learn more about asphalt roofing, visit ARMA at www.asphaltroofing.org.
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