Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
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
FLAT ROOF MOISTURE & CONDENSATION
Green House or Solarium Roof Leaks
HEAT TAPES & CABLES on Roofs for Ice Dams
ROOF ICE DAM LEAKS
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.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
Workmanship and Wind Damage Assessment for Asphalt Shingle Roofs
As stated in Best Practices Guide to Residential Construction:
In cold, cloudy weather or on a steep north-facing slope, manual sealing with roofing cement may be necessary.
Roof Installation Workmanship:
Fasteners/Nailing Problems, Wind Damage appeared to have led wind blow-off of these Atlas shingles, though an investigation of whether or not the shingles had self-sealed was also needed.
Weather: Wind damage can happen to any asphalt shingle roof in severe weather conditions.
However if shingles are not properly nailed, shingles are far more likely to blow off of the roof in even a modest windstorm.
Proper roof shingle nailing is what keeps shingles on the roof in a high wind
Roofing product manufacturers are careful to specify where shingle nails should be placed in each shingle and the number of nails required.
In addition to the number of nails, how nails are driven is critial to a shingle's ability to stay on the roof.
Sketch (above/left) of common roof shingle nailing errors is a detail from FEMA's , Asphalt Shingle Roofing for High Wind Regions .
How Roof Shingle Nailing Errors Occur
Over-driving nails so that they cut into the shingle or driving nails on an angle so that the edge of the nail cuts into its shingle as well as the next overlapping shingle are examples of common errors.
Below Mr. Skees elaborates on the importance of nailing errors in roof shingle blow-offs. First a little background: How or why does this angled or over-driving of roof shingle nails happen? Roofers depend on speed to make a profit. A roofer moving very fast may use excessive air pressure or nailing gun settings so that s/he can drive nails very rapidly. But improper gun settings over-drive nails, cutting shingles and allowing them to blow off of the roof. And a roofer who reaches out with the nailer (speed again) rather than taking a step is also more likely to drive nails on an angle.
These specifications may vary by shingle type and building location, with more nails specified for high-wind areas such as asphalt shingle roofs applied in coastal areas.
Just How Important is Nailing in Roof Shingle Wind Damage Prevention?
High Nailing Roof Shingles
When Hurricane Ike turned east after landfall in Texas in September 2008 and tracked up the Ohio River Valley, we had thousands of wind damage claims. I looked at several hundred. All of them I inspected were shingles that were improperly nailed. Most of the missing and torn shingles were nailed above the sealing strips.
Pneumatic Roof Nailer Pressure Settings
Another common nailing issue that leads to unnecessary wind damage is over-driving the nails, most often when pneumatic nailers are used.
Perhaps the most common cause of shingle blow-off in storms is improper or inadequate nailing by the roofing installer.
I don't remember a single wind damage claim where the nails were in the proper location and driven flush with the surface of the shingles. The instructions are usually printed on the packaging, complete with diagrams. In both English and Spanish.
With the compressor set too high, the heads cut through the fabric of the shingle, basically leaving the shingles unattached to the roof.
Another discussion of shingle nailing errors and omissions is at Mr. Skees' comments about LADDERING vs STAIR STEPPING SHINGLES
Follow the Manufacturer's Shingle Nailing & Placement Instructions
Commentary: D Friedman
On a wood shingle failure where all of the shingles were improperly offset the roofer was trying to bluff his way through, insisting that his work was absolutely to spec and correct and in accordance with the manufacturer's instructions. A pile of swept-up debris remained in the courtyard (this was a big expensive roof job).
Taking the roofer aside, away from the client (and from unnecessary embarrassment) I reached into the pile and pulled out one of the inserts from the manufacturer that showed the shingle offset pattern they wanted and the nailing pattern - which was totally different from what he had used. The result was cursing and fist shaking and stomping off the job. The client, however, read and recognized the significance of the manufacturer's instructions.
As Skees points out
Reading the instructions doesn't take but a moment, and it would be a great idea.
Components of roof shingle wind damage resistance
Not only must nails be properly placed and spaced, improper nailing itself, such as driving a nail through the shingle, leaving a nail sticking up to cut a shingle above, or using a roofing stapler improperly leaving cocked staples or shingle-cutting staples will all encourage shingles to fly away with the wind.
If an new roof has the bad luck to encounter a severe wind storm shortly after asphalt shingles have been installed, it is possible that the shingles will blow off of the roof because their self-sealing tabs have simply not had time (or warm enough weather or enough sun) to adhere.
For FEMA advice on wind damage resistant construction of roofing, see "Asphalt Shingle Roofing for High Wind Regions, Home Builders' Guide to Coastal Construction" [PDF], FEMA 499, August 2005, Technical Fact Sheet No. 20.
Roofing Shingle Glue Strip or Glue Tab Adhesion Failure as Contributor to Wind Damage to Asphalt Shingle Roofs
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.
Questions & answers or comments about how to recognize, diagnose, repair & prevent wind damage to roofs.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website