Constructor - November/December 2015 - (Page 41)

Beyond Insulation SPRAY FOAM CAN OFFER DURABLE, VERSATILE ROOFING SOLUTION BY PETER DAVIS CHAIRMAN AND CEO, GACO WESTERN A STRONG AND WELL-BUILT roof is the first defense in protecting a structure from the corrosive effects of the outside environment, aiding in temperature control and helping to prevent the intrusion of natural elements like wind, rain, ice and snow. One product that has proven to be a versatile and durable choice as a roof system is spray polyurethane foam (SPF), especially for existing structures in need of a roof replacement. This is because in addition to serving as an insulation product, SPF provides an air and moisture barrier, is lightweight, and expands on application, making it installable on most surfaces and in tight spaces. In fact, for more than 40 years contractors and builders across the country have been using high-density closed-cell SPF as a roofing product. This type of SPF typically carries a high R-value (measure of thermal resistance), protects against water and air intrusion and has a compressive strength that can support foot traffic on the roof. Henderson - Johnson Co. Inc., an AGC of New York State LLC member, has been installing SPF as a roofing material for more than 35 years and recommends it to its customers based on the positive long-term results they have seen in the more than 30 million square feet they have installed. Henderson - Johnson Vice President Todd Henderson said that while it works for both new and existing construction, it can be especially well suited as a replacement roof on commercial and industrial structures with low-slope roofs. "One big benefit of spray foam roofs is they'll go over approximately 95 percent of existing roofs," he explained. "That's in part what it was designed for. You can use it on a new roof or a complete tear off, but it is very effective when used over existing roofs." WHY SPRAY FOAM? An SPF roofing system provides insulation and air and water barriers in a single @Constr uctor Ma g layer, which can be laid directly on a building's sub-roof or on top of a previous roof installation, though it should be noted that most local building codes limit the number of roofing installations that can be layered on top of each other. Flat roofs, also known as low-sloped roofs, and pitched metal roofs are generally great candidates for an SPF system, as spray foam is usually able to seal and strengthen the roof without compromising or requiring a complete removal of the existing system. And as a lightweight roofing system, SPF will typically put minimum additional stress on a building's structure. Henderson says that for old roofs that are starting to rust and leak, SPF is able to seal them and help prevent and eliminate An SPF roofing system provides insulation and air and water barriers in a single layer, which can be laid directly on a building's sub-roof or on top of a previous roof installation. multiple problems ranging from heat loss to issues with ice. "As roof seams fail, or the fasteners fail, and water gets in the batts of insulation, it is useless as an insulator," he explained. "So you get a lot of heat loss and you get water dripping down into the building. We've sprayed those and helped alleviate those ice problems." For flat roofs, SPF can often be installed seamlessly across the top and, because of its spray on nature, can be easily fitted around rooftop equipment and systems, such as climate control units. SPF roofing systems tend to eliminate seams typical of other systems, removing potential access points for water to leak down into the Photo courtesy of Henderson-Johnson Co. Inc. structure. Building codes require a degree of slope, usually ranging from an eighth to a quarter of an inch per foot, to prevent water from settling and leading to potential structural and other damage. This can be achieved on an SPF system by installing it in a graduating pitch and ensuring any drains are lower than that pitch; in some structures, settling has disrupted the original flow. The SPF can also fill in any additional low spots on the roof, reducing the likelihood of pooling. THE RIGHT INSTALL To ensure a quality and long-lasting roof system, it is important to choose an SPF installer that has the experience and the know-how to do the job right. SPF itself is produced by mixing an isocyanate (methyl diphenyl diisocyanate or "MDI" in the case of SPF) and a polyol blend, which react to form the polyurethane. To ensure maximum results, they are mixed at the jobsite to create foam that expands within seconds to the desired thickness. Like many construction products and building materials, SPF needs to be handled with care and properly installed, using the right equipment and materials. Trained professional installers use a combination of personal protective equipment and jobsite NO V E MB E R / D E C E MB E R 2 0 1 5 | 41

Table of Contents for the Digital Edition of Constructor - November/December 2015

Editor’s Note
President’s Message
CEO’s Letter
Play It Safe With BIM
Workforce Shortage Report: Western Region
Taking Off: The Unique Nature of Airport Construction
Pack Your Boots and Don Your Hat
Simonson Says
Shape Up and Ship Out
AGC San Diego Opens Fall Protection Campus
Inside AGC
Beyond Insulation
Member and Chapter News
Technology Toolbox
2015 Software Services Guide
Index to Advertisers
Final Inspection

Constructor - November/December 2015