National Coatings Blog

Asphaltic and modified bitumen roofing membranes comprise one of the largest segments of the low slope roofing market. The asphalt used for roofing is usually blended with reinforcing agents such as calcium carbonate to increase strength and decrease flow. If the material is modified bitumen, the asphalt is blended with a polymeric modifier such as atactic polypropylene (APP) to create APP-modified bitumen or styrene-butadiene-styrene (SBS) block copolymers to create SBS-modified bitumen. Two variants are SEBS (styrene-ethylene-butadiene-styrene) and SIBS (styrene-isobutylene-styrene) block copolymers. 

Asphalt is a by-product of the crude oil refining process. After the "lighter fractions" are distilled off, (gasoline, kerosene, diesel fuel, grease) the remaining crude oil, called flux, is the basic building block for asphalt and modified bitumen. While asphalt has excellent waterproofing properties, it is extremely susceptible to attack by UV radiation. The deterioration that is observed as cracking and chalking is a direct result of this attack.  The underlying mechanism is twofold. Chemical analyses of asphalt have shown it to be composed of hundreds of different chemical components. Some of these components are liquids at room temperature, but when dispersed in the asphalt matrix, appear to be solids. Over time and with the addition of heat (IR), these light fractions leach out. This has two effects. First, the loss of this material slightly reduces the size of the roofing material (i.e. volume reduction). This loss of dimension, or shrinkage, may cause stress on the seams and fasteners, reducing the service life of the roof. Moreover, these light fractions also act as plasticizers, making the membrane more flexible, especially at low service temperatures. Some of the stone granules that protect the bitumen cap sheet may become dislodged and collect in the gutters and low spots on the roof. This is a result of the loss of these asphalt fractions that act as "glue" to adhere the granules to the asphalt surface. As the granules become dislodged, more asphalt is exposed to the harmful effects of the sun's UV and IR radiation. This, in turn contributes to a more rapid degradation of the asphalt membrane.

An additional weathering related reaction is that of oxygen in the air with some of the components of the asphalt. This chemical reaction causes the asphalt to become less hydrophobic, as hydroxyl radicals are created on the component chains. This reaction can be observed by wetting aged asphalt with water and checking for a soapy feel. The soapy "feel" is the result of the asphalt reacting with oxygen. 

Understanding the fundamental mechanism for asphalt deterioration now enables us to identify methods for extending its service life. If the asphalt can be protected from the harmful effects of UV, keep it cooler, and prevent its contact with oxygen, it will last longer. This can easily be accomplished through the use of white, UV blocking roof coatings, such as those of the AcryShield product line.

National Coatings AcryPly Roof Restoration System and AcryShield Roof Maintenance Systems are ideal for renewing and restoring your existing Asphalt, BUR, or Mod Bit roofing membranes.  These systems allow you to gain a brand new, leak-free, monolithic roofing system without the extra cost, time and stress of a traditional roof replacement/roof tear-off system. Restoring your aged asphalt roof saves you time, money and allows for a cleaner environment. These systems are ideal for businesses that cannot afford to be closed during construction and application. For more information on our non-intrusive roofing systems, download our FREE Benefits Brochure or contact us at 800-423-9557.

AcryShield A550 has Double the Toughness with Urethane-Like Strength
A550 top coat can be applied as a multi-purpose base and top coat. It has double the toughness of any other AcryShield coating. With its urethane-like strength and elongation properties, this product is excellent for superior protection against foot traffic and physical abuse. A550 exceeds ASTM D6083.

AcryShield A590 has ULTRA High Reflectance with Superior UV Protection
A590 can be applied as one coat over smooth substrates. Guaranteed to lower air conditioning energy costs and reduce roof degradation, prolonging the life of the roof, significantly lowering the life-cycle costs of the roof even more than our other cool roof products. A590 exceeds ASTM D6083.

QuickSet Products are Formulated to Resist Early Wash-Off Associated with Light Rain and Heavy Dew
AcryShield A600, A610 and A640 top coats and A602, A603 base coats can be applied to virtually any roofing substrate. Don't let light rain and heavy dew weather conditions stop you from completing your roofing job.

AcryShield A410 Vapor Retarder
A410 is a low-perm elastomeric base coat for SPF, specifically designed for the exterior of buildings and rooms where there is reverse vapor drive. Excellent for cold storage facilities, food packing plants, etc...

Color Options:
AcryShield coatings come in four standard colors - white, sand, light gray and dark gray. Custom colors are available upon request.

AcryShield A400 Has Unique Asphalt Bleed-Blocking Properties Excellent for Top Coat Over Asphalt
A400 was developed specifically for areas in warm to moderate climates where temperatures do not drop below 0ºF. A400 provides longevity and brightness with superior dirt pick-up resistance and protection against biological attack such as algae and mold. AcryShield A400 has excellent tensile strength, elongation, wet adhesion and weatherability, it exceeds all of the ASTM D6083 requirements except for low temperature flexibility.

AcryShield A500 is excellent over Asphalt, Single-Ply, SPF, Metal & Concrete Roofing
A500 can also be used as a base and top coat for both SPF and metal roofing. A500 provides longevity and brightness with superior dirt pick-up resistance and protection against biological attack such as algae and mold. A500 was developed specifically for areas where extra levels of low temperature flexibility is required (areas where temperatures drop below 0ºF). AcryShield A500 exceeds all ASTM D6083 requirements and also offers excellent tensile strength, elongation, and wet adhesion.

AcryShield A502 Base Coat for Hard to Coat Surfaces such as Hypalon, TPO, EPDM, & PVC Roofing
AcryShield A502 base coat is the industry standard, low VOC, high performance base coat. A502 base coat eliminates the need for costly TPO replacement and provides unique AcryLock technology to tenaciously adhere directly to EPDM, TPO and Hypalon without the need for additional primers or an etching rinse. A502 provides an additional layer of waterproofing, superior adhesion, and resistance to ponded water.

AcryShield A503 Base Coat for Asphalt & Concrete Surfaces
AcryShield A503 base coat is a one component, low VOC, water-borne base coat with unique wet adhesion properties specifically designed to adhere to asphalt, mod bit and concrete surfaces, allowing for superior protection against ponded water and eliminating the need for costly roof replacement.

AcryShield A510 Excellent in Place of A500 in Areas Where Additional Fire Retardant Packages are not Required
A510 can be applied over asphalt, single-ply, SPF, metal and concrete roofing. A510 can also be a base coat for both SPF and metal roofing. A510 exceeds ASTM D6083.