A disheartening sound this time of year often is the drip, drip, drip of a roof leak. Unfortunately, most of us wait for rain or snow before checking on the condition of the roof. What's worse, it is usually during a violent storm that a roof leak occurs, making it virtually impossible to take immediate action.

We're sure those of you in this circumstance will agree that it would have been prudent to water-test the roof for leaks before the first serious rains or snowfall. So much for an ounce of prevention. There are maintenance measures that can be taken that will help prevent roof leaks.

One of the best is to limit traffic on the roof. In the movie "National Lampoon's Christmas Vacation," Chevy Chase traipsed about the roof affixing Christmas lights. Walking on the roof is often all that's needed to cause a leak. If you must, knowing where to step will lessen the possibility of damage and the potential for a fall.

Due to its flat profile, this detail is not as important with a composition shingle roof as it is with shakes, tile or metal. The latter three are more vulnerable to damage; shakes split, tile cracks and metal dents. Avoid stepping on cupped or curled shakes. The flatter the shake the less likely it is to be damaged. Step on the beefiest part near the butt end. Tile, cement and fiber-cement products can be particularly vulnerable. Each has its own particular sensitive spots. Your best bet is to seek advice from a local roofing contractor as to where to tread.

A roof that is clean and free of debris is less likely to leak. Leaves, pine needles and moss are all enemies of a roof and will, more often than not, inhibit watershed and cause a dam effect. This backup of water can get between the layers of roofing and waterproofing membrane causing a serious roof leak. A ball or a child's toy have been known to be the cause of a backup.

Among the most effective ways to remove debris from the roof is with a pressure washer. A power blower-vac, a broom and a garden hose can also be useful, but require more elbow grease. The best method to remove moss is with a power washer. A periodic rinsing with a solution of one cup of liquid chlorine bleach in a gallon of hot water is a practical way to get rid of moss and prevent its return. A zinc or copper strip applied at the ridge of the roof is another effective method of preventing moss. A potential disadvantage is streaking.

A buildup of ice at the eave an ice dam will cause a roof leak and can even result in structural damage to the roof framing system. While there are several methods of preventing an ice dam, one of the best is by using an eave-heating system. Eave heaters consist of a network of wires that are strung on the roof above the overhang. These wires work essentially like those in an electric blanket. They keep the water from becoming ice and allow for proper watershed.

Two elements of the roofing system that can be major causes of leaks are the gutters and downspouts. Debris-laden gutters and-or clogged downspouts will allow water to back up, preventing it from being properly discharged. Gutters should be periodically cleaned. Leaves and other debris that have been allowed to sit for a long period of time will create a mulch-like mud material that can be difficult to remove. A small garden trowel can be used to remove the bulk of this material.

After the mass of bulky material has been removed, a leaf blower-vac will remove what remains. Finish the job by using a garden hose with a high pressure nozzle to flush the system out. The garden hose works especially well as a snake to dislodge clogged downspouts and drainage pipes.

A preponderance of water at the perimeter of or under the house can result in everything from dry rot to cracks over windows and doors. Thus, water collected by gutters and downspouts should be discharged away from the home. Ideally, the water should be transported by a solid drain pipe into the municipal storm drain system, a drainage trench or non-erosive riprap. Also, soil and pavement surrounding the house should be graded to drain away from the foundation.