With wet weather on the way in many parts of the country, now is the time to inspect your roof.

A roof leak can result in significant damage to insulation, walls, ceilings, flooring and personal property. If undetected, a leak can cause rot that will endanger the structural integrity of the roof framing system and cause costly repairs.

The larger the leak, the greater the damage, however, we have seen pin hole leaks in galvanized sheet metal flashings that have required the replacement of an entire ceiling.

According to the National Roofing Contractors Association (NRCA), a roof should be inspected at least twice annually once in the fall before the rains and again in the late spring to determine how it fared during winter, the season toughest on a roof.

Most homeowners can inspect a roof for troubled areas and, if handy around the house, can make the required repairs. If, on the other hand, you have a fear of heights or otherwise feel uneasy about attempting such a project, many professional roofing companies will provide a free inspection and provide a written estimate outlining the required repairs.

If the thought of climbing on the roof brings on high anxiety, consider using a pair of binoculars for a closer look. It's a good idea to limit traffic on the roof to prevent damage to shingles or tiles.

Using the binoculars, look for loose shingles or shakes, or, if you have a tile or slate roof, for missing or cracked pieces. On shingle roofs, look for curling, fraying, and tears at the edges. Check the flashings around chimneys, vents, skylights and other roof penetrations. They should be tight and in good condition.

Good flashings, especially those at roof edges and penetrations, are crucial. Many roof leaks are actually flashing leaks. Rusted flashings should be cleaned up, repaired and painted with a rust-resistant paint. Severely deteriorated flashings and vents should be replaced.

Leaves, pine needles and other debris inhibit the roof's ability to properly shed water, and are the cause of water backing up between shingles or around flashings. Clogged gutters and downspouts are another cause of leaks. Clear sticks, leaves, tennis balls and other debris from drains, scuppers and gutters. Bad drainage is only slightly better than no drainage.

Sometimes a visual inspection of the roof isn't enough to determine where a leak exists. In this case, a water test is in order. You'll need to venture atop the roof to do this effectively. Use a firmly braced or tied-off ladder equipped with rubber safety feet and wear rubber soled shoes to avoid slipping.

Using a garden hose, run water onto the areas where a leak is most likely. For example, if there is a water stain on the ceiling just in front of the fireplace in the living room you'll want to concentrate on that general area with your water test. The chimney flashing may be the culprit in this case and a water test is sure to expose it.

It's useful to have a helper located in the attic when performing this test. He can readily detect where the water is making its way through the roof.

When making the water test, work your way up from the lowest part of the slope. This makes it easy to tackle one area at a time and allows you to work on a dry surface.

Once the source of the leak is found, you'll either attempt the repair yourself or call in a professional roofing contractor. Sometimes a dab of roofing adhesive, a touch of caulking or a small shingle patch is all that's required. Other times flashing, vents or sections of roofing must be torn out and replaced, in which case hiring a roofing professional would be wise.

If your roof is fifteen years or older or has leaked periodically, its condition should be evaluated once annually by a roofing contractor. For some older roofs, repairs are temporary at best and a new roof should be considered to preserve the integrity of the home.

If you decide to install a new roof, there are two alternatives: re-covering installing a new roof over the existing one or replacement wherein the old roofing is removed. While some building codes will allow the application of up to three layers of roofing, we recommend that all existing roof cover be torn off before the new roof is installed.

Frequently the roof sheathing or wood decking below the roof cover is rotting as a result of leaks or excessive condensation due to poor attic ventilation. The only way to effectively inspect and repair this damage, is by removing all of the existing roof cover. Furthermore, having the roof sheathing exposed is a prime opportunity to look for protruding nail heads that can damage roofing, and become the source of future leaks.

Another disadvantage to multiple layers of roofing is the weight that is placed upon the roof structure. Too much can cause rafters and other roof framing members to sag or even fracture.

When selecting a contractor, remember that all are not alike. A new roof is a big investment take your time and make a smart decision. Use good common sense and follow these guidelines:

Ask friends and neighbors for the names of contractors they have used and would recommend.

Look for a company with a proven track record. Be sure the contractor has a permanent business address and phone number.

Be sure the contractor is licensed (where required) and check with the licensing agency to check the status of the license. Get three to four written estimates.

Call your local Better Business Bureau to find out if there are any complaints on file against the contractor.

Ask for a list of customer references and take the time to check them out.

Be certain the contractor carries liability and worker's compensation insurance. Ask for certificates of insurance.

Insist on a warranty for both materials and workmanship, and at contract time, get it in writing.

Be sure everything is in writing scope of work, materials, warranties, price, and start and completion dates.

Be wary of contractors with very low bids. They may have to cut corners to make a profit. Remember, price is only one of the criteria for selecting a contractor.

For more information on hiring a roofing contractor and to receive a booklet titled "Buying a new roof and getting your money's worth," write the National Roofing Contractors Association, 10255 W. Higgins Road, Suite 600, Rosemont, IL 60018-5607.