Sprayed-in-place polyurethane foam has been protecting buildings since the 1960s. By now, everyone seems to have formulated an opinion on foam roofing. Love it or hate it. Big headlines--Superdome, Kingdome, Tacoma Dome. It's easy to, understand why foam has been used on arenas. It's the lightest roofing system around. It is an excellent insulator. It can be used on any slope, and reflective coatings can he applied. Hurricane Andrew brought out additional virtues. Not only was the foam resistant to blow-off, but it accommodated flying missiles as well. Foam roofing is maintainable and recoatable. With a decent recoating schedule--it's best to recoat when pinholes first appear--a foam roof--can last for decades.
W hat's the negative side? First, ignorance! Many readers of this column are roofing contractors and consultants who may be very knowledgeable on BUR, modified bitumen and single-ply systems, but who have never sprayed foam. When asked to look at an existing foam system, they're ill-equipped to rehabilitate a blistered, cratered or flaking foam system. They are smart enough to know that bituminous patches on foam are predestined to fail. Roofing contractors are reluctant to enter the spray foam business. It's different, complicated, equipment intensive, and the economics are uncertain. They're more likely to, tell the owner to tear the foam roof off and put down something they do know how to handle.
A nother negative has been the lack of information where it's needed most. There's an excellent trade association, The Polyurethane Foam Contractors Division of The Society of the Plastics Industry (PFCD of SPI). PFCD has initiated an accreditation program requiring training and field inspections, but PFCD is relatively small and its programs are not well known. Now PFCD has joined forces with the National Roofing Contractors Association to Fill this gap. A field survey will be conducted to look at existing installations and to see what's working and what's not. A literature survey will highlight excellent work already accomplished by the U.S. Bureau of Reclamation, Corps of Engineers, U.S. Navy Civil Engineering Laboratories and the Del Webb School at Arizona State University.
T he NRCA's long awaited Roofing and Waterproofing Manual will soon be available. The NRCA has updated and expanded their foam section. Both NRCA and PFCD now offer guide details as well as specifications. ASTM has published a Standard Guide D5469 For the Application of New Spray Applied Polyurethane Foam and Coated Roofing Systems and is close to completing a similar guide for recovering existing roofs.
With all this resource material and a new study of foam performance, it should be easier to know if sprayed foam roofing is right for your business.
W hat does all this mean? Far more information will soon be available. For contractors--should they express an interest in this business--the technical information will be on hand with the credibility of the NRCA behind it. For building owners, dubious because of the "horror-stories" they've been told, the field survey should be reassuring. Earlier work by Dean Kashawagi at Arizona State indicated many foam roofs have lasted 20 years or more and appear to last indefinitely if maintained. Dr. Kashawagi also discovered that owners have been extremely satisfied with the performance of their foam roofs.
T his survey should answer questions pertaining to minimum foam density, types of coatings for differing climate conditions, film thickness, maintenance procedures and whether gravel foam roofs are worth considering. Should the survey be as positive as Dr. Kashawagi's earlier work, perhaps some skeptics will be willing to take another look. RSI
©Reprinted from ROOFING, SIDING, INSULATION, June 1995 |