Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
Ask a Question or Search InspectAPedia
InspectAPedia ® Home
ROOFING INSPECTION & REPAIR
AMERICAN CEMWOOD ROOFING
BEST ROOFING PRACTICES
BUILT UP ROOFS
CATHEDRAL CEILING VENTILATION
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY FLASHING Mistakes & Leaks
COLD WEATHER ROOF TROUBLE
DECKS, ROOFTOP CONSTRUCTION
EPDM, RUBBER, PVC ROOFING
EXTRACTIVE BLEEDING on SHINGLES
FIRE RETARDANT PLYWOOD
FLASHING on BUILDINGS
FLASHING, ASPHALT SHINGLE VALLEYS
FLASHING, CHIMNEY Mistakes & Leaks
FLASHING, CLAY TILE ROOFS
FLASHING MEMBRANES PEEL & STICK
FLASHING for METAL ROOFS
FLASHING ROOF WALL DETAILS
FLASHING ROOF-WALL SNAFU
FLASHING SIDING DETAILS
FLASHING WALL DETAILS
FLASHING WINDOW DETAILS
FLASHING WOOD ROOF DETAILS
FLAT ROOF MOISTURE & CONDENSATION
Green House or Solarium Roof Leaks
HEAT TAPES & CABLES on Roofs for Ice Dams
ICE DAM PREVENTION
MASONITE WOODRUF FIBERBOARD ROOFING
NOISE CONTROL for ROOFS
PLASTIC ROOFING TYPES
PVC, EPDM, RUBBER ROOFING
ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
ROOF CLEANING RECOMMENDATIONS
ROOF COLOR RECOMMENDATIONS
ROOF DORMER TYPES - PHOTO GUIDE
ROOF INSPECTION SAFETY & LIMITS
ROOF JOB PROBLEMS, RESOLVING
ROOF LEAK DIAGNOSIS & REPAIR
ROOF NOISE TRANSMISSION
ROOF REPLACEMENT SNAFUs
ROOFING FELT UNDERLAYMENT REQUIREMENTS
ROOFING MATERIALS, Age, Types
ROOFING TILE SHAPES & PROFILES
ROOFING UNDERLAYMENT BEST PRACTICES
SADDLE CONSTRUCTION at CHIMNEYS
SNOW GUARDS & SNOW BRAKES
STANDARDS for ROOFING
STRESS SKIN INSULATED PANELS
TEST LABS - ROOF SHINGLE
TREES & SHRUBS, TRIM OFF BUILDING
TRUSSES, Floor & Roof
UNDERLAYMENT REQUIREMENTS on ROOFS
VENTILATION in BUILDINGS
WALK-ON ROOF SURFACES
WARRANTIES for ROOF SHINGLES
WORKMANSHIP & ROOF DAMAGE
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?"
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
What is the Purpose of the Glue Strip on Asphalt Roof Shingles?
This asphalt shingle adhesive strip is intended to bond to the three tabs of the next shingles nailed atop of this one when the roof is later warmed by sunlight.
On occasions, particularly during high wind conditions such as hurricanes, defective glue strips or adhesive strips on the underside of asphalt shingles may not provide sufficient adhesion, or if the shingles were not properly handled and the glue strip was dirty, an adhesion failure can lead to failure of the shingle tabs to adhere to the nailed-down header of the shingle above. In this case exposure to high winds can cause shingles to tear or blow off of the roof, increasing the degree of water damage inside the building when such winds are accompanied by rain.
In most climates exposure to even a few weeks of normal sunlight will cause the glue tabs on the under-side of asphalt roof shingles to soften and adhere to the surface below.
We discuss the function of asphalt shingle adhesive strips, handling the protective cellophane strip, and shingle uplift wind damage prevention in more detail at WIND DAMAGE to ROOFS.
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.
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.
WIND RESISTANCE/HAND SEALING: These shingles have a special thermal sealant that firmly bonds the shingles together after application when exposed to sun and warm temperatures. Shingles installed in Fall or Winter may not seal until the following Spring. If shingles are damaged by winds before sealing or are not exposed to adequate surface temperatures, or if the self sealant gets dirty, the shingles may never seal. Failure to seal under these circumstances results from the nature of self-sealing shingles and is not a manufacturing defect.
To insure immediate sealing, apply 4 quarter-sized dabs of shingle tab adhesive on the back of the shingle 1" (25mm) and 13" (330mm) in from each side and 1" (25mm) up from bottom of the shingle. Press shingle firmly into the adhesive. For maximum wind resistance along rakes, cement shingles to underlayment and each other in a 4" (102mm) width of asphalt plastic roof cement. [More details about this are at WIND DAMAGE to ROOFS]
Watch out: Excess tab adhesive can cause blistering of the shingle.
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.
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.
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:
Asphalt roof shingles sold today (2009) in high wind zones are totally different from what we used in the early 90’s. Forget the number of nails also, four is fine for most shingles used today. The problem was not number of nails but failure of adhesion. Today’s high wind shingles can’t be pulled apart once they seal.
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.
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 
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
Questions & answers or comments about about the cellophane strip protecting the glue strip on asphalt roof shingles: should it be removed or not?
Ask a Question or Enter Search Terms in the InspectApedia search box just below.
Related Topics, found near the top of this page suggest articles closely related to this one.