Your Roof and Hail Storms

When hail storms come thundering along, they mean trouble of a particular kind for your roof. No roofing system is hall-proof. But there are roofing materials with hail-resistance ratings. These are provided by the American Society of Testing and Materials (ASTM).

You can choose a material rated one through four (four being most resistant.) They achieve this rating by dropping a steel ball from a pretermined height onto the roofing material and determining the damage.

Many roofs carry this rating. For steep slope, these roofs include some metal roofs, some tile and some composition shingles. For flat roofs, these are some gravel-surfaced built-up, and some spray foam (with the right coating system), and just a few others.

Installing a Class IV hail resistant roof may qualify you for lower insurance premiums, depending on where you live. Call your agent for verification. Keep this in mind, too: not many agents and adjusters will know the specifics about hail resistant roofs. Consult either a good roofing contractor or your local roofing supply warehouse.

Since World War II scientists have tried many techniques to lessen the damage from hail storms. The most well-known technique involved "seeding" large thunderstorms with silver iodide. The theory was that the resulting small hail would probably melt and therefore not cause any damage. Unfortunately other experiments using this technique were not successful, and hail suppression remains elusive.

Another novel technique to supress hail was recently installed in a company parking lot by an auto manufacturer trying to protect its inventory of newly painted cars. Under certain thunderstorm conditions detected by the company's own radars, a cannon-like device will send sonic waves up to 50,000 feet in the air to keep hailstones from forming. Now they must wait for a hailstom to pass over the parking lot to test the device!

(Information from roofhelp.com)

Wind Damage

Strong winds can provide a substantial amount of damage to roofing systems. Generally, they are not designed to withstand winds of hurricane or tornado intensity.
However, roofs may also be damaged by winds of moderate intensity, with gusts that may reach 50 to 75 miles per hour.

Mostly, this is caused by the partial vacuum created by wind blowing over the edge of the roof. Nature tries to neutralize the low-pressure area by bringing in air from a higher pressure area, usually from inside the building. This air pushes up on the bottom side of the roof assembly and, over time, loosens fasteners and breaks the adhesion making the roof more susceptible to damage from the next moderate or strong wind.

To counteract the effects of wind-uplift forces, the roofing and insulation should be adequately fastened to the roof deck, and a securely-fastened perimeter detail should be provided.

Roof Leaks

Many roof leaks are the result of nail holes. It's not unusual for nail holes in the shingles or flashing to increase in size over time allowing water to seep around the nails. Before a roof leak causes damage to your home and punctures your pocketbook, you'll need to pinpoint the source of the leak. And for that we'll head to the attic.

From inside the attic, scan the framings with a flashlight. You're looking for drops of water, or stains. It's best to do this after a rainstorm or as snow melts. On sunny days, you can sometimes spot a nail hole as the light shines into the dark attic. To keep on top of nail holes on your roof, here are some leak-proof pointers:


* Caulk and seal any holes you find on the roof using roofing cement. Cover nail heads with roofing cement when nailing in shingles.
* Inspect your roof twice a year. Replace shingles that have holes that are too large to patch.
* Remember leaks can be sneaky; they may not take a direct route. If you can't find the source of a leak, get professional help.