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Spraying Foam over Composite Shingles Post New Topic | Post Reply
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Posted: Jun 17, 2008 02:45 PM
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Spraying Foam over Composite Shingles
Hi Mason,We are about to begin a project on a older commercial building. The building has five sloped pitched that have composite shingles. Between the pitches are flat 6 foot wide flat areas with smooth surface tar/asphalt covered with an acrylic coating. My question relates to foaming over composite shingles? Is this ok? Do some loose shingles need to be re-adhered with caulking or a nail gun? Or would you recommend a tare off? Kindly, www.roofcrafterswest.com |
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mason
Posted: Jun 17, 2008 03:51 PM
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SPF can be installed over asphalt shingles without tear off. It typically adheres very well, but you would want to nail down shingles in areas that are loose. If there are two shingle roofs, you need to tear off the existing roofs. Also, you need to check out the wood decking to make sure it is OK. Older shingles that are very brittle are not good substrates for SPF. One thing, the foam will look funny to some folks kinda like snow if it is done right. If not applied evenly, it can look pretty gross. You use a nominal 3 lb density SPF with an elastomeric coating over it that has been rated with the foam as a class A b or C roof covering. Your foam manufacturer can assist with providing the correct system. Once in place the SPF roof needs to be recoated on average every 15 years. Check out SPFA's technical guidlines on new and redial roofing (AY 104) and guideline for elastomeric coatings (AY 102). You can download the documents at sprayfoam.org. Look in the technical section. |
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Posted: Jun 18, 2008 02:32 PM
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Thanks for the info, Mason. I will read more of those technical documents on the SPFA website. Brian www.roofcrafterswest.com |
