Severe Weather and Your Roof, Part 2: Heavy Wind
By J-Conn Roofing, Monday, May 12, 2014
Wind Damage

When homeowners envision the forces of nature that can damage their roofs, hail, snow, ice, and heavy rain are usually the items that first come to mind. Wind, though, also can be a destructive force that causes roof problems.

According to a report from the International Association of Certified Home Inspectors, wind damage can be either direct or indirect. Indirect damage is caused by objects — tree limbs, lawn furniture, loosened sections or shingles of a damaged roof portion, etc. — that are propelled by wind to impact your roof. Direct damage occurs when wind is the force acting directly on the materials covering your roof.

The shape and orientation of a house and the type of roof are factors contributing to the damage caused by wind. When wind strikes a house in such a way that it blows parallel to a standard roof ridge, the shingles are less likely to sustain damage. However, if the shingles along the edge meeting the prevailing wind are in poor condition — i.e., already damaged or loosened — they are more likely to suffer from the lift caused by strong wind, which can cause a peeling effect. Peeling of shingles from the side of the roof or from drip edges causes an even larger area of your roof to be susceptible to further damage.

Shingles positioned in the vulnerable areas are most prone to wind damage if they are improperly installed. The number of nails used and the placement of those nails are the major factors in susceptibility to wind damage. Proper nail position is straight down into the decking, and the nails should not be driven so hard as to cause the nail head to be below the top layer of shingles. Not only can this crack the shingle, but the “dimple” created can cause the edge of the shingle to jut up just enough to allow entry for a lifting wind.

According to Best Practices Guide to Residential Construction, many common shingles carry a resistance rating for winds up to 60 mph; specialty shingles might be rated for winds as strong as 130 mph. Though it is common to encounter such wind speeds during tornadoes and hurricanes, gusts of wind at such speeds can occur at any time of year, even when no cyclonic weather systems are active.

Wind damage to a roof can be cumulative or occur from just one severe weather event. Such damage should be repaired at the earliest opportunity; exposed areas of your roof, even small areas, provide easy entry for rain and make adjoining sections of the roof much more vulnerable to further damage from wind or other severe weather events.