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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
Guide to assessing, repairing & preventing wind damage to roofing: this document discusses how to evaluate wind damage to asphalt shingle roofs and tells readers how to identify & explain the most-common failure mechanisms such as improper nailing, failure of shingles to seal. This information is useful when considering how to obtain asphalt roofing shingle failure claims assistance. These defects occur on both organic-mat or fiberglass-mat asphalt roof shingles. Readers are also invited contribute roof failure information to the web author for research purposes. web author for research purposes. Readers should also see ASPHALT SHINGLE INSTALLATION. For clay or concrete tile roofs, see CLAY TILE WIND & SEISMIC CONNECTORS where we describe special connectors used for roofing tiles in high wind, hurricane, and seismic areas. Standard clay tile roof connectors are discussed at CLAY TILE ROOF CONNECTIONS.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Workmanship and Wind Damage Assessment for Asphalt Shingle Roofs
As stated in Best Practices Guide to Residential Construction:
Proper roof shingle nailing is what keeps shingles on the roof in a high wind
Just How Important is Nailing in Roof Shingle Wind Damage Prevention?
Roofing Shingle Glue Strip or Glue Tab Adhesion Failure as Contributor to Wind Damage to Asphalt Shingle Roofs
Our photo (left) shows a typical 3-tab asphalt roof shingle (this one is made by GAF™). The shiny black strips form the "glue line" on the shingle. This adhesive 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 below.
In cold climates, the asphalt shingle sealant strip may not set up properly and may require manual sealing.
For three-tab shingles, place two quarter-size spots of plastic roof cement under the lower corners of each tab (as shown in Figure 2-7).
With laminated shingles, place four to six quarter-sized dots, spaced evenly, about one inch above the bottom of the overlapping shingle.
Our page top photo shows the standard sealant strips found on asphalt shingles, in this case a GAF® product we photographed at a Home Depot® store.
Here is what the GAF Materials Corporation, Grand Timberline™ Premium Architectural Shingle Application Instructions say about the glue strips and cellophane. You'll note that we are to leave the cellophane in place, but if site conditions (high wind) require immediate shingle sealing, an extra step, using additional shingle tab adhesive, is permitted.
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.
NOTE: Excess tab adhesive can cause blistering of the shingle. [The company is referring to the use of additional roof shingle adhesive, not the factory-applied glue strip. Also see BLISTERS on ASPHALT SHINGLES -- InspectAPedia]. 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.
The success with which asphalt shingles bond together as the glue strip is heated by sun exposure is a factor in protecting roof shingles from wind-damage and blow-off. But the debate about whether or not a protective cellophane strip found atop this glue strip on new asphalt shingles has gone on too long. Do we remove the cellophane or leave it in place?
A detailed article about this question is at CELLOPHANE STRIP REMOVAL?. Excerpts are just below.
Our photo (left) shows the cellophane strip found on the back or "down"
No: In answer to a common reader question, not normally: according to roofing manufacturers, it is not required to remove the cellophane strip on the back of roof shingles before they are nailed. Below we quote from a major manufacturer's instructions.
Yes: as we discuss in more detail at CELLOPHANE STRIP REMOVAL?, experts familiar with wind damaged roofs (in coastal areas exposed to hurricanes and in other high-wind areas) previously recommended both the removal of the cellophane strip and the installation of double-sticky-sided roofing adhesive mastic tape or roof cement under shingle tabs at the time of asphalt roof shingle installation.
As Cramer reported in 2009 (see "More on the "yes" answer" just below, currently asphalt shingles sold in high wind areas adhere and cannot be pulled apart by wind (nor hand).
Certainly if you wait to remove the 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. causing also extra foot traffic wear.
The photographs here include examples of improperly or inadequately-nailed shingles which blew off in modest windstorms of far less than hurricane strength. In the first photograph below, our correspondent has laid-out shingles retrieved after the storm, showing the location and pattern of nail holes in each shingle - clear evidence of just how they were nailed. Our ridge cap shingle loss (above left) is plainly due to wind damage. The shingles falling off of the barn roof (above right) appear due to a combination of wind damage and possibly inadequate nailing.
FASTENERS: Use of nails is recommended. Use only zinc coated steel or aluminum, 10-12 gauge, barbed, deformed or smooth shank roofing nails with heads 3/8" (10mm) to 7/16" (12mm) in diameter. Fasteners should be long enough to penetrate at least 3/4" (19mm) into wood decks or just through the plywood decks. Fasteners must be driven flush with the surface of the shingle. Over driving will damage the shingle. Raised fasteners will interfere with the sealing of the shingles.
Experts discussing measures to reduce asphalt roof shingle blow-off in coastal or other high-wind areas recommend against using roofing staples to install shingles.
UNDERLAYMENT: Underlayment beneath shingles has many benefits, including preventing wind driven rain from reaching the interior of the building and preventing sap in some wood decking from reacting with asphalt shingles. Underlayment is also required by many code bodies. Where an underlayment is to be installed, use a breather-type underlayment such as GAF Shingle-Mate® underlayment.
ROOF DECKS: Wood decks must be well-seasoned, supported, and tightly-constructed with maximum 6" (152mm) wide lumber, having adequate nail-holding capacity and a smooth surface. Plywood decking as recommended by The Engineered Wood Association is acceptable. Where a Class A rating is required over decks less than 15/32" thick, an underlayment is required. Do not fasten shingles directly to insulation or insulated deck unless authorized in writing by GAF. Roof decks and existing surfacing material must be dry prior to application of shingles.
In discussing wind damage to roofing with your insurance adjuster or roofing contractor, be sure to review the details of original and replacement shingle installation as this can give evidence about the underlying cause of roof failure as well as informing you of how to avoid roof shingle blow-off in the future.
For FEMA advice on wind damage resistant construction of roofing, see "Asphalt Shingle Roofing for High Wind Regions, Home Builders' Guide to Coastal Construction", FEMA 499, August 2005, Technical Fact Sheet No. 20.
We live in Texas and recently had high winds. We lost some shingles and the rest were flapping in the wind, meaning the seals were broken. Will these seals "heal" with the heat we have in Texas, or do they need to be replaced?
- M.T. 4/17/2013
In general if the shingle did a lot of flapping I'm afraid it may be cracked, worn, such that the tab may break off - an on-roof inspection would be needed to decide. I'm a little worried that a shingle tab may have been weakened without showing a visible crack, but I figure especially in a warm climate like yours an asphalt shingle tab can tolerate some pretty good bending without becoming cracked. That's not true in colder areas of the country.
I would not rely on the previously-sealed shingles to re-seal themselves properly once they've been lifted by a windstorm. The fact that the shingles were flapping and have broken seals makes me suspect they may not seal reliably again - after all they failed the first time and so are weaker than before.
IF the shingles appear undamaged but not sealed, you should be able to improve their sealing with a dab or two of roof cement beneath each tab.
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