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UNDERLAYMENT REQUIREMENTS on ROOFS
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Cellophane strip found on / between asphalt roof shingles: this article describes the cellophane strips found between individual asphalt roof shingles - atop the glue strip. We explain the purpose of this cellophane strip. We answer the question: " Should we remove the cellophane strip when nailing shingles or should it be left in place?"
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What is the Purpose of the Glue Strip on Asphalt Roof Shingles?
Certainly if you wait to remove the protective cellophane strip until the moment that the shingle is about to be nailed, taking it off will do no harm, and it may speed the adhesion between shingles that is intended to resist wind blow-off of roof shingles. We suspect that few professional roofers will add to their roofing time and cost by taking a step that is not recommended by the product manufacturer.
Roofing Manufacturer's Advice about the Cellophane Strip on Shingles
At ASPHALT SHINGLE INSTALLATION we include this quote from the GAF Materials Corporation, Grand Timberline™ Premium Architectural Shingle Application Instructions say about the glue strips and cellophane.
You'll note that according to the manufacturer we are to leave the cellophane strip in place, but if site conditions (high wind) require immediate shingle sealing, an extra step, using additional shingle tab adhesive, is permitted. [Italics ours.]
Our photo at left illustrates the "Miami-Dade County Approved" imprint found on the underside of an asphalt shingle that meets Florida's wind-resistance requirements.
In the warning just above the company is referring to the use of additional roof shingle adhesive, not the factory-applied glue strip. Also see BLISTERS on ASPHALT SHINGLES. The film strips on the back of each shingle are to prevent sticking together of the shingles while in the bundle and to keep dirt and debris out of the adhesive material so that after installation the adhesive will work. Their removal is NOT required during application.
More on the "no" answer to removing roof shingle cellophane strips
Our photograph of the cellophane strip in place on the underside of an asphalt roof shingle (left) clearly shows that the shingle manufacturer says "Do Not Remove This Tape".
The cellophane tape on the back side of asphalt roof shingles is intended to prevent the glue strips from becoming activated prematurely, in storage or shipping, and equally important, to keep the glue-area clean during the roof installation process: jobsite debris (sawdust, dirt) can prevent the sealant from adhering.
Once the roof is installed the heat from sunlight will activate the sealing mastic through the cellophane. It does not need to be removed as part of the roofing process.
Actually, trying to remove the strip after installation might also risk damaging the shingle since you'd have to run along the roof slope lifting nailed-down shingle tabs to try to (unnecessarily) pull off the cellophane - risking tearing shingles and causing also extra foot traffic wear. Indeed a few times we have seen actual pits and holes in the backs of shingles when a roofer ripped off the cellophane that was very bonded to the shingle surface.
More on the "yes" answer to removing roof shingle cellophane strips
One of our readers, Leonard Wheeler, reported that independent analysis of wind damaged roofs concluded that "... many shingles and attachment adhesives used were not adequate for the wind speeds that occurred. The most common failure mode was lifting of the tabs due to failure of the self-seal adhesive, and subsequent tearing of the shingles at the fasteners (Smith, 1994)."
Our associate, Mark Cramer, a Florida home inspector and educator in the field, reported that houses suffering damage during Hurricane Andrew were generally those not built to code, and that code-built homes survived the hurricane with minimal damage. Mr. Cramer provides this update:
Other measures to reduce water damage to buildings in coastal or high wind areas include use of roof flashing tape or strips of ice-and-water-shield type products over the butt joints between sections of plywood or OSB roof decking. The presence of roofing felt under shingles won't prevent roof leaks after shingles are installed, since the shingle nails will have made thousands of penetrations in that membrane.
A Forensic Engineer's View on Cellophane Strips on Asphalt Roof Shingles
The only time the cellophane strip protects the seal strips is while they are still in the package.
I am a forensic engineer who works for insurance companies. Occasionally I find a limited number of shingles on a roof did not seal because the cellophane strips have attached to the seal strips instead of staying on the underside of the shingles in the package. Let me try to explain that better.
The cellophane strips are attached to the center of the undersides of the shingles at the factory. The seal strips are on the top side at the center of the shingles.
The only time the cellophane strip protects the seal strips is while they are still in the package. Occasionally stacks of shingles are left out in the sun before they are installed, sometimes while at the distribution center, sometimes at the factory, sometimes on the truck that delivers them, sometimes in stacks in the yard before they are installed, and even sometimes across the roof before the roofers open the packages.
In those cases (you see above they can be many cases), the solar radiation can activate the sealing strip adhesive on the top shingle or two or maybe even three, and the cellophane attaches to the top side of the shingle covering the adhesive when the shingles are taken out of the bundle.
Most of the cellophane strips have the instructions not to remove printed on the surface. However, it will be printed in reverse when it sticks to the seal strip (since it is intended to be read from the bottom). However, to most of us that read English it still admonishes that it not be removed, even if it is printed backwards.
With the cellophane in place covering the sealant, the shingles installed over those individual two or three (per bundle) will never seal. This leads to blow-off failure more often than you would think.
I find several like this every year and there may be as many as ten to 15 complete missing shingles on a single roof because of the cellophane sticking to the seal strips.
That is usually enough to put the insurance company on the hook for an entire roof that somebody installed incorrectly.
- James A. Skees, PE 
Opinion on When to Remove Cellophane Strips on Asphalt Shingles -DF
Based on the above our opinion is that you may and should leave the cellophane strips in place on the shingle back surface (which is ok with the manufacturer) so long as the strip is intact and in its original position.
But when installing an asphalt shingle roof if you encounter cellophane strips that have already come loose, you may as well remove them and dispose of them off of the roof. The roof will look like a junky installation if there are inches of cellophane blowing in the breeze all over the new roof.
Watch out: Do not leave loose cellophane strips nor any other extraneous debris on a roof, especially when installing new roof shingles as those materials may interfere with proper roof tab sealing and may lead to future increased shingle blow-off in windy conditions.
About deliberately pulling off all of the tabs: if you are in a high wind area and are going to be adding additional sealant anyway, this step is probably unnecessary and is not specified by the manufacturer.
Earlier, in the 1990's we were concerned with excessive bonding between shingles that combined with a lack of tear resistance to lead to premature roof failures due to thermal splitting. It's fair to add, however, that the root cause of that problem was a specification that led to inadequate tear resistance, not an innate fault with shingle tab bonding. See CRACKS in FIBERGLASS SHINGLES
Frequently Asked Questions (FAQs) about the cellophane strip protecting the glue strip on asphalt roof shingles: should it be removed or not?
Question: so what happens to the plastic or cellophane strip? If we knew we might stop arguing about whether to remove the strip from shingles or not
[In the article above] you really should include an explanation from someone about what happens to the cellophane strip in the normal adhesion process. Does it break down and allow direct contact? Does it react with the sealant allowing the sealant to pass through?
Does the sealant simply flow around the strip to achieve adhesion? A proper understanding of any process is key to once-and-for-all removing doubt as to the correct interpretation of a procedure. Someone must know how this works. - D.C. 6/13/2013
Reply: the sealant protection strip is offset from the adhesive strip when the shingles are nailed in place - they no longer touch: leave the sealant strip in place
I certainly appreciate your comment and agree that your question is one that many people ponder. I thought we'd driven the nail in the coffin of this debate by citing the manufacturer's advice above, but your comment is a reminder that we never explained just what happens to the cellophane or "plastic" strip - if anything does happen for that matter.
The company explains that the plastic sealant protection strip is not biodegradable, does not dissolve, melt or anything else. [We add that this means if you could pull off these strips, against the instructions of the manufacturer, you're creating a mess of stuff blowing all over the site: debris that does not magically disappear on its own.
The placement of the asphalt shingle sealant protection strip is the key.
GAF explains that when shingles are in the bundle the plastic (or "cellophane") strip on the underside of a shingle surface is positioned so that it prevents sticking of that shingle to the self-sealing adhesive on the upper surface of the shingle beneath.
But when the roof shingles are installed according to specifications, the location of successive shingle courses will make sure that the stick-preventing plastic strip (bonded to the underside of a shingle) will be offset from the actual location of the sealing adhesive of the shingle course below.
You can see this by noticing where the adhesive strips are in an installed asphalt shingle roof in our illustration (above left). On the topmost shingle in our illustration, the cellophane strip on that shingle would be on the shingle underside exactly the same distance from the shingle top as is the adhesive strip on that shingle - placing the strip a good 4-inches above the adhesive strip on the course below. Here is how GAF puts it:
So there is no need to remove the plastic/cellophane strip and further, it should not be removed. Why not? Well in some cases tearing off the strip may remove shingle material, thus damaging the shingle and reducing its life.
In any event, the guideline on leaving the strip in place is clear and unequivocal. Let's hope that with GAF's help we've driven a nail into this popular roofing legend. GAF Technical services can be contacted online or by telephone as we cite in our references below.
Questions & answers or comments about about the cellophane strip protecting the glue strip on asphalt roof shingles: should it be removed or not?
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