One of the most vulnerable spots on your home is the roof. And one hazard most homeowners can expect to face at some point is hail.
Compared to earthquakes and hurricanes, hail might seem like a minor concern. True, hailstorms don’t cause the loss of life, but they can shatter windows, leave pockmarks in siding and, most important, destroy or damage roof coverings. Here are some tips to help you protect your investment.

How do you know if a roof covering is impact-resistant?
One way is to look for Underwriters Laboratories’ measuring stick: the UL 2218 standard. The UL test involves dropping steel balls of varying sizes from heights designed to simulate the force of free-falling hailstones. Four impact-level designations will help you compare products: roof coverings that show the most resistance earn a Class 4 rating; the least, a Class 1 rating.

You put a lot of time, work and money into your home. Naturally, you want to use the best products available. In terms of roof coverings, this means a UL 2218 rating of Class 4.  A Class 4 rating tells you that a sample of the product did not crack when hit twice in the same spot by a 2-inch steel ball, which, in a storm, would translate into quite a hailstone. A Class 1 rating signifies resistance to a 1 1/4-inch steel ball; Class 2, a 1 1/2-inch steel ball; and Class 3 a 1 3/4-inch ball.

The UL 2218 standard is the best method to test impact resistance, but it isn’t perfect and works better for some coverings than for others. UL 2218 measures whether a product cracks under impact. Some roof coverings, in particular some made of metal, may resist cracking but can be dented and dimple. So while they test well, they may perform poorly in practice. Keep this in mind when using the UL standard as a gauge of quality. And to cover all the bases, also check for wind-resistance features and a fire-resistance rating. Consult a design professional, your insurance company or roofing installer about steps you can take—  fastening vulnerable rows of asphalt shingles with adhesive, for example,  or tying down tile with a screw and wire instead of nails— to help your roof covering stand up better against high wind.

Fire ratings range from Class A materials that are effective against severe fire exposure to Class C materials that are only effective against light exposure. Products that are untested or have failed a test are listed as “nonrated.”

Although asphalt shingles are the most common, roof coverings come in a variety of colors and styles. Which is best for your home.

There are many different types of residential roof coverings to choose from.

What type best suits your taste and the level of hail risk where you live?

Asphalt shingles are found on most homes in the United States and can be reinforced with either organic or fiberglass materials.

Fiberglass shingles last up to 20 years and have a Class A fire rating.

Modified asphalt shingles include SBS (a rubber-type compound) or APP (a plasticizer) and are likely to perform well in hailstorms. Without them, fiberglass composition shingles stand up moderately well to hail.

Metal, primarily thought of as a commercial roofing material, has become an attractive alternative for some homeowners. Not only do they last up to 40 years, metal roofs are also relatively lightweight and may have a Class A or B fire rating. But beware of their performance in hailstorms. Unlike other shingles that can ease back into shape, metal can dimple permanently.

Slate tends to be long-lasting (up to 100 years) but also more expensive than other materials. And you would need someone with skill and experience to apply it, which can add to the cost. Another point to consider: slate is very heavy. Some roof structures are unable to support this type of roof covering. Be sure to check with a registered design professional before spending all of that money.
Synthetic roof coverings (e.g., fiber cement or molded plastic) simulate various types of traditional roof coverings, such as slate and wood shingles and shakes. Their performance varies by product.

Tile is popular in some areas, but its performance in hailstorms varies by type. Concrete tiles are more durable and can last more than 20 years, while clay tiles are brittle and can be easily chipped or broken. And another thing: like slate, tile is heavy. If you are replacing another type of roof with tile, you will need to verify that the structure can support the weight. Also, heavy products can take longer to install, so labor costs may be significantly more.
Wood shingles and shakes are made from cedar, southern pine or other woods. Though some like their appearance, wood shingles and shakes perform only moderately well against hail. Two other things to consider: 1) some local codes limit their use; and 2) unless they’re treated with a fire retardant, they may not have a fire rating.

Before making your roofing selection, take your time and check out the variety of products. Look at full-size samples of the roof covering you’re considering. You can also get information by looking at manufacturers’ brochures or visiting a house that is roofed with a particular product. Most roofing materials will come with some type of warranty, but they have limited value. Even the most comprehensive warranties will not cover all damages under every circumstance. Be sure to read the fine print.

Roofing products have changed significantly over time. The variety of choices in materials, appearances and prices allows you to get the look you want without compromising quality. Above all, look for materials that will protect your home for many years.
Information compiled in cooperation with the National Roofing Contractors Association.

Of course you’ll want to carefully evaluate any contractor you consider so you can be confident the job will be done right.

Your insurance company may be able to give you names of qualified roofing contractors in your area. Or, you can contact the National Roofing Contractors Association at 1-800-USA-ROOF for assistance or check its website (www.nrca.net).

Here are some things to consider:

• Look for an established, licensed or bonded roofing contractor. Ask for references and call them up.


• Ask to see certificates of insurance. Make sure that both liability and workers compensation insurance coverages are carried and are in force while roofing work is being done.


• Insist on a detailed, written estimate that clearly states the quantity of materials needed; labor charges; work specifications, including approximate starting and completion dates and payment procedures.


• Carefully review and understand any warranty and watch for conditions that would void it.


• Be skeptical about lowest bids or those considerably lower than others written for the same job. Many contractors seem attractive because of low bids; however, they may be uninsured and may perform substandard work. If it looks too good to be true, it probably is.


• Contact your local Better Business Bureau to check for complaints filed against the contractor.

[Adapted from material supplied by the National Roofing Contractors Association.]

Won’t the experts pick the best roof covering for me?
No. Building codes do not require that roofs be impact resistant, so don’t rely on codes or regulations to protect you. And if you are having a home built, don’t assume that the architect or designer will do your planning for you. For the most part, they call for a generic type, such as wood shakes, asphalt composition shingles, or clay or concrete tiles. If you are putting on a new roof covering or replacing an existing one, it’s up to you to make sure your new roof covering will resist impacts, especially if you live in a hail-prone area.

I have insurance. Why should I worry about hail damage?
Sure, standard homeowners policies will cover hail damage. But that doesn’t mean you’re free and clear and can just leave the problem to your insurance company. All policies have some kind of deductible or co-payment. No matter what your type of coverage, as a homeowner, you will be reaching into your own pocket to repair or replace a roof damaged by hail. Repairing or replacing a roof covering is a major inconvenience. Knowing which roof coverings resist impact well, and which do not, can save you a lot of trouble and a lot of money.

What causes a roof to wear out?
Several factors can speed a roof’s decay, including ultraviolet light from the sun and temperature extremes in your area. Exposure to wind, snow, ice and rain and foot traffic on the roof don’t help either. Darker color shingles, because they absorb more light, may have shorter service lives than lighter colors in southern climates.

Why do wood roof shingles split and crack?
Wood naturally splits and cracks as part of the aging process. This is largely due to swelling and shrinking caused by moisture and subsequent drying.

Can an existing asphalt shingle roof be covered with another?
A roofing contractor may be able to apply the new material directly on top of the old layer, depending on its condition. Although this saves a little bit of time and money, experts strongly recommend against it, especially in hail- or wind-prone regions. Hail tends to cause more damage when there is more than one layer of shingles. In windy areas, the new layer will not grab as tightly as it should if there is a pre-existing layer under it. Any other type of roof covering is typically removed before the new roof covering is installed.

Can composition shingle roofs be repaired?
Yes. If damage is minor, a roofing contractor can remove individual shingles and replace them.

Can’t I just do the work myself?
Only if you have sufficient experience in replacing roof coverings. Otherwise, don’t try it. Most roofing jobs are not for the do-it-yourselfer. Novices can do more harm than good if they use improper roofing techniques. More importantly, they can severely injure themselves by falling off or even through a roof. Professional roofing contractors are trained to do the job safely and efficiently.

What sort of ongoing maintenance should I do?
Inspect the roof in the fall and spring for cracked or curling shingles, and clean rain gutters filled with dead leaves and other debris. It's best to use binoculars and do this from the ground. If you really feel that you need a closer look, use a firmly braced or tied-off ladder equipped with rubber safety feet. Wear rubber-soled shoes and stay on the ladder (and off the roof) if possible so you don’t damage your roof or yourself.

Deck/Sheathing:
The surface — usually plywood or oriented-strand board (OSB) — to which roof underlayments and coverings are applied.

Dormer:
A small structure projecting from a sloped roof, usually with a window.

Drip edge:
An L-shaped strip (usually metal) installed along the edges of the roof to allow water to drip clear of the deck, eaves and siding.

Eave:
The horizontal lower edge of a sloped roof where it extends past the outer wall of the house.

Fascia:
A flat board, band or face located just below the eave.

Flashing:
Pieces of metal used to prevent water seepage around any intersection or projection in a roof, such as vent pipes, chimneys, valleys and the joints at vertical walls.

Louvers:
Slatted devices installed in a gable end wall or in a soffit (the underside of the eaves) to ventilate the space below the roof deck and equalize air temperature and moisture.

Rake:
An extension of the roof over a wall at the gable end.

Ridge:
The top edge of two intersecting sloping roof surfaces.

Slope:
Slope is measured by rise in inches for each 12 inches of horizontal run. A roof with a 4-in-12 slope rises 4 inches for every horizontal foot, for instance. The steeper the slope, the more difficult the repair and more costly the labor.

Square:
The most common measurement for roof surfaces, it equals 100 square feet (10”x10”).

Underlayment/Felt:
A sheet of asphalt-saturated material (often called “tar paper”) used as a secondary layer of protection for the roof deck. It is rolled out on top of the roof deck and sits under the roof covering.

Valley:
The angle formed at the intersection of two sloping roof surfaces.

Vapor Retarder:
A material designed to restrict the passage of water vapor through a roof or wall.