Release Film


Technical Bulletin #24

Current as of March 2016



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Asphalt shingles have been a commonly used roofing material for almost a century. Early asphalt shingles were often applied with an asphalt or tar adhesive to enhance wind resistance. In the 1950’s shingles were introduced with a factory-applied asphalt adhesive sealant strip. The sealant strip on those shingles was protected by an overlying loose film that needed to be removed during shingle installation.

By the late 1950’s, manufacturers had developed an alternate way to protect the factory-applied adhesive. Rather than a cumbersome “removable” film, they merely applied/adhered a smooth film on the bottom of the shingle in the exact area that contacted the sealant strip of the shingle below while the shingles were packaged in the bundle. This release film prevents the sealant from “activating” while the shingles are in the bundle. (The sealant on the top shingle in each package is protected by special treatment applied to that area of the bundle wrapper.) Once the shingles were unpacked and arranged on the roof for installation, the protective film had served its purpose and could be left in place. Early release films were sometimes aluminum foil or special paper, but now clear plastic is most common.

This manufacturing practice is still used by manufacturers today. The tape on the back of asphalt shingles does not need to be removed. In fact it is not really designed for removal, so it is often quite difficult to remove! Removing this film will in no way help the shingles bond faster, seal to each other better, or last longer on the roof.

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The information contained in this bulletin is for general education and is not intended to replace advice from a qualified contractor or direction on usage/installation from the manufacturer. Consumers should be aware of the safety hazards associated with work on roofs and, before doing so themselves, should consider following CASMA s advice of using qualified contractors. This bulletin may be reproduced with permission on condition that it be reproduced in whole, unedited, with attribution of copyright to CASMA.

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