APPLICATION TEMPERATURES

whether hot or cold, can change the physical properties of coatings, sealants, primers, and adhesives. Applying liquid-applied products outside their recommended temperature window may lead to performance issues. Equally important and related to temperature, the relative humidity should be 85% or less and ambient air temperature must be 5°F above the dew point at the time of application.

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Viscosity Change

     ·       Cold temperatures will increase the viscosity (thickness) of a product and hot              temperatures will decrease viscosity. This can affect the rate of application,              causing too much or too little product to be applied.

Application Rates Matter!  

     ·       Applying a product at the incorrect rate (too thick) can lengthen cure times              (adhesives/primers), affect reflectivity (aluminum coatings),or cause blistering              (solvent & water-based coatings).  

Curing

     ·       For products that cure by evaporation of solvent or water, warm air allows for              quicker evaporation as long as the relative humidity is below 85% and the ambient              air temperature is 5°F above the dew point.  For moisture curing products, warm air              holds more moisture helping trigger curing mechanisms.  Colder air is dryer and              holds less moisture so evaporation is slowed and moisture reliant curing is drawn              out longer.    

Appearance

     ·       Aluminum coatings require the sun’s heat to help the aluminum pigment leaf to the              surface.  As the solvent evaporates, the pigments remain on the coating surface to              produce a consistent, reflective film.  

Blushing

     ·       This is when moisture vapor condenses on the surface of a liquid-applied product              due to evaporation of the solvent when applied in warm, humid, or cold, damp              weather. The moisture layer will slow evaporation and curing and may affect the              appearance and reflectivity of a coating.    

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RECOMMENDED APPLICATION TEMPERATURE CHART

Weather plays an important role in the application of liquid-applied roof products.  Make sure you STAY WEATHER-AWARE by downloading a weather app to keep you informed of current conditions on your project site.

For any questions, contact KARNAK Technical Services at 800-526-4236 or info@karnakcorp.com.