Protective roof coatings serve a variety of applications and purposes. The art of a quality coating specification depends on a thorough evaluation of current roof conditions, combined with an understanding of the owner’s budget and expectations. At Truco, we strive to align these interests to maximize the value and performance of any restoration effort.
To establish credible objectives, it helps to understand the benefits and limits of fluid applied roofing materials. Truco manufactures a variety of coating types – elastomeric coatings, aluminized asphalt, silicones, acrylics and urethanes. Most of Truco’s protective coating applications are based upon thermoplastic (SEBS) rubber polymers. Truco has been working with thermoplastic formulation technology for 30+ years and pioneered the application of these fluid applied elastomeric coatings. The essential nature of the SEBS polymer is its strong and lasting adhesive characteristics, low moisture permeability, high reflectivity and exceptional chemical resistance. Acrylic and silicone formulations also have merit, especially when low odor options are critical and higher perm, “breathable” coating films are advantageous.
In most cases, the cured SEBS coating’s adhesion to a conventional roof membrane (modified bitumen, TPO, Hypalon, etc.) will exceed that materials bond to its own felts or reinforcing scrim. Properly applied, the coating essentially becomes a durable part of the existing roof and, by virtue of its low permanence, can weather well in low slope roofing environments. The polymer is used in flat conditions, where it withstands ponding water.
However, the cured film is sensitive to moisture vapor drive from within the roof assembly, which can result in blisters or fissures forming over time. Therefore, core cuts and/or infrared moisture surveys are valuable in detecting portions of the roof assembly that retain entrapped moisture. Replacing portions of the roof assembly that are not suitable for simple resurfacing is an essential aspect of a good coating specification. On metal roofs, low perm/vapor barrier coatings are ideal for protecting the metal, as the self-priming rubber prevents oxygen or moisture from accessing the substrate. They also provide durabile performance on low slope metal or membranes in Northern climates, where the presence of ice, snow and moisture are expected on the coated surface for extended periods of time.
Thermoplastic rubber effectively seals moisture from entry via metal roofs at seams, fasteners, curbs, etc. It also prevents moisture capillarity, or pin holes, from forming in roof membranes that have lost mil thickness over time to chalking, or have been compromised by hail events. In many cases, moisture seepage into the roof assembly is of greater economic consequence to the owner, than active leaks into the building itself. As a consequence of seepage, insulation boards, fasteners, and decking can all be subject to deterioration. Resurfacing an older roof to assure its fundamental capability as a moisture barrier, is as important as relieving active leaks within the building envelope.