The Sustainable Season of Roofing Adhesives for Contractors
As stated in the third chapter of Ecclesiastes and sung by the Byrds, “To everything there is a season.” For roofing adhesives today, the roofing industry has entered a new season that may or may not relate to the actual seasonal weather conditions we face on the roof. As concerns about air quality have grown, governments have introduced new regulations to reduce ground-level ozone that leads to smog formation in the atmosphere directly above urban areas. Although much of this ozone may be attributed to the smokestacks of factories and the tailpipes of automobiles, a measurable portion of ground-level ozone is produced by volatile organic compounds (VOCs) used as solvents in paints and adhesives. As a result, regulations restricting the amount of VOCs allowed in construction coatings and adhesives have spread across the United States.
In order to adapt to VOC regulations, roof system manufacturers have developed new generations of adhesives that require little or no VOC content. Some of these adhesives rely on a high-solids content, while others use one- or two-part urethanes to reduce or eliminate the need for VOCs. But the majority of new formulations substitute water for most of the high-VOC solvents previously used in roofing adhesives. Adhesives have always been affected by weather conditions, but today’s water-based roofing adhesives are much more sensitive to weather than solvent-based adhesives used in the past. Application at low temperature and high humidity may be challenging, especially when outdoor conditions approach freezing or the dew point. In addition, water-based adhesives tend to use softer resins that are easier to dissolve; but these resins may lack the “legs” or strength of other polymers used with stronger organic solvents.