b'Photo of GAFs United Coatings Diathon acrylic coating being applied by sprayer. Photo courtesy of GAF.The Key to a Successful Roof CoatingRoof Coating Application and Performance Tipsby James R. Kirbyfrom theBuildingEnclosureOnline.comWinter 2017 Building EnclosureR oof coatings are designed formaintenance. Some of the items to watch fordripping sweat into the coating while mixing protecting and extending the serviceduring and after a roof coating applicationit. A crew that fails to check the ambient life of roof assemblies for newinclude spray-application problems, storagetemperature, surface temperature, relative construction and more commonly, existingconcerns, environmental conditions, lack of roof coverings, such as BUR, metal, modifiedmaintenance and foot traffic.bitumen, single-ply, and spray polyurethaneSpray-Application Problemsfoam. Roof coatings are formulated to provide protection for many years against the damagingThe vast majority of spray-application effects of weather and the environment, suchfailures are the result of an applicators lack of as UV light, and excessive water and wind.experience and equipment-related issues. Spray The most common types of roof coatings areapplication equipment must always be within acrylic coatings, asphalt coatings, polyurethanespray manufacturer specifications. There are coatings and silicone coatings. different brands, different pumps, different For existing buildings, every building ownerpressures, and different hoses and tips. Onehumidity and dew point prior to application will eventually be faced with the decision tomust be vigilant in their efforts to keep all ofcan cause widespread installation problems. completely tear-off an existing roof, to recovertheir equipment within the parameters set forthProper training and quality control oversight it or to repair it. About 3,000,000,000 square- in the specification. Even when all of thesecan avoid many costly mistakes.feet of roofs are either replaced or re-coatedrequirements are met, several factors can affectStorage Concernseach year. Given that roofing materials are theapplication such as roof height, length of hose, third greatest contributor to waste in landfills,coating and ambient temperature, and wornRoof coatings are formulated to react a roof coatings are an ideal solution to extend thespray-tips. This can lead to over-spray, clogging,certain way under certain conditions. For service life of an existing roof and prevent tear- lack of pressure, improper spray fan pattern,example, improper storage of moisture-cured off and waste. Roof coatings extend roof serviceetc. coatings can lead to a moisture-triggered life because they reduce rooftop temperaturesImproper storage or maintenance of sprayreaction taking place in the container before it by reflecting radiation from the sun, protectapplication equipment can cause problems onis applied. Roof coatings should normally be the membrane below the coating from furtherthe job. Using the wrong lubricating oils andstored in a climate controlled space, where the degradation, and provide an additional weatherflushing liquids in a spray rig can cause failurecoating will not reach freezing temperatures, resistive layer for long term performance.in a coating system. Failing to replace a wornand generally never exceed 110 degrees Reflective roof coatings also help to reduce thetip when spraying can lead to overspray issuesFahrenheit. Roof coatings should be kept in the urban heat island effect. and coverage rate problems. shade, covered from the elements, and kept on raised platforms or pallets. The shelf life of each Application and Maintenance It is paramount to have an experienced spraypackage/pail should be observed, and materials Two keys to the successful performance of aapplicator. For example, an inexperiencedshould be properly disposed of when expired. roof coating are proper application and regularapplicator can ruin a batch of moisture-curedFailure to follow proper storage guidelines from or solvent-based coating on a hot day simply bya manufacturer can result in costly failures in 24 www.mrca.orgMidwest Roofer'