RainShield® – Seamless Single-Ply Built-Up Roofing Systems



Rainshield® Commercial Roofing Systems Demo


RainShield® Commercial Roofing Systems are lightweight, high-performance, sustainable, Cool-Roof systems. Originally developed in the early 1940s, these systems were first used extensively on military installations. They were preferred over other systems because of longer life cycles, greater installation safety in high pedestrian traffic areas, cost effectiveness, renewability, and ease of maintenance. Acclaim for the system spread rapidly throughout the building and real estate industries and by the 1960s RainShield® systems had been adopted as the roofing system of choice for most public school districts in the southwest. RainShield® is still to this day the most widely used roofing system for schools, is still specified for work on military bases, and is well established as one of the top roofing system choices for commercial building owners and property managers.

RainShield® Systems are best described as a hybrid of single-ply and built-up roofing systems. RainShield® takes the best from both to provide a superior, long lasting, sustainable roofing system that building owners and property managers can specify and install with the confidence of 70 years of successful system performance. Every roofing system has three basic components: Waterproofing, Reinforcement, and Reflectivity. The combined performance of these components dictates reliability and longevity for any roofing system. RainShield® Systems employ the highest performing products in each category to provide the lightest weight, most durable, and longest lasting commercial roofing systems available.

The waterproofing component of RainShield® Systems comes from a base of waterproofing grade asphalt. Waterproofing grade asphalt comes initially from the same source as roofing grade asphalt but is processed differently. Roofing grade asphalt is processed by super heating in an updraft blast furnace, removing much of the light naphthenic oils by oxidizing and aerating the product. This hardens roofing grade asphalts, making them easy to store and transport but the end result is a degraded product that no longer has the UV stability, waterproofing or adhesive properties that it once did. Waterproofing grade asphalt on the other hand is never super heated, aerated or prematurely oxidized before use. It remains in a liquid state during initial processing which preserves the light oils that provide asphalt with flexibility, adhesion, and most important; waterproofing. Prior to application, waterproofing grade asphalt is further enhanced in a colloidal mill with the addition of Bentonite clay, a waterproofing agent commonly used in exterior sub-grade damp-proofing applications. The resulting UV stable waterproofing grade asphalt provides superior waterproofing, elasticity, and adhesion for all RainShield® Commercial Roofing Systems.

Roofing system reinforcement, especially in Sunbelt states, is critical to system performance and longevity. Daily roof temperatures in the Southwest can swing from 30 – 50 degrees in the early morning to over 120 (Cool-Roof) or 180 (Rock or Capsheet) degrees or more in the same afternoon, depending on system UV reflectivity. Regardless, expansion and contraction from heat is the number one killer of roofing systems, twisting, pulling and tearing at fasteners, terminations and seams during daily thermo-cycles, eventually resulting in mole-runs, cracks and splits in a roof. There are two commonly used roofing system reinforcement products used today; fiberglass and polyester. RainShield® systems use lightweight high-performance stitch-bonded polyester for reinforcement in all their commercial roofing system specifications. Polyester is 300% stronger and 100% more elastic that that of the fiberglass reinforcements typically used in built-up rock or capsheet roofing systems. Strong elastic polyester and flexible waterproofing grade asphalts give RainShield® systems an edge over the completion when the heat is on.

Long lasting reflectivity is critical to roofing system longevity. There isn’t a product or compound known to man that can be set out unprotected in the sun to weather and age for years that won’t be adversely affected by the sun’s damaging UV rays. RainShield® Roofing Systems are by design almost completely UV inert. Waterproofing grade asphalt is UV stable and further system protection is provided by highly reflective, long lasting, acrylic elastomeric surfacing. The acrylic surfacing used to protect RainShield® Systems is applied in two phases, the first is gray UV blocking elastomeric acrylic designed to keep the Ultra Violet radiation from the roofing system and second is ultra white UV reflective elastomeric acrylic designed to reflect the heat of the sun and keep the roofing system and building below cool. Cool-Roofs are not subject to the extreme punishment from daily thermo-cycling that other roofing systems are exposed to. In fact, a cool roof cannot heat to a temperature more than 15% higher than the ambient temperature. This design characteristic prevents the extreme heating of the waterproofing grade asphalts used in RainShield® systems so the light oils are never heated to a point where they could oxidize and if the acrylic surfacing is maintained, a RainShield® Roofing System could be sustained well beyond the useful life of the building, and in many cases they have.