One of the many reasons for the growth of self-adhered membranes is they contain little or no VOCs and meet even California’s strictest emission standards.
The same cannot be said of solvent-based adhesives. For this reason, specifiers are turning to water-based (WB) and low VOC (LVOC) adhesives when adhering single-ply membranes.
Unfortunately, the roofing industry has become concerned with the longer drying times exhibited by WB and LVOC adhesives. This is especially true when ambient temperatures and dew points “converge” up on the roof.
Installation problems include blistering and/or inadequate adhesion of the membrane to the substrate, as well as drying times approaching 1.5 hours or more. Roofing contractors, roof consultants and specifiers must be made aware of these prolonged drying times and take precautionary measures in the field to ensure proper adhesion of the membrane to the substrate.
In contrast, adhesives on self-adhered membranes are uniformly applied in the factory, while field-applied adhesives can be fussy — too much adhesive can damage the system, and too little can compromise the bond.
It’s also important that the industry give roofing professionals the analytical tools needed to predict drying times, while requesting that architects are more flexible when specifying adhesives. If a LVOC product is required but does not flash off adequately, the architect and property owner will have to live with the results.