Winter months can be cruel to your roof, your home's first line of defense against high winds, heavy rains, sleet or snow. If your roof fails, it can cause great expense, significant damage and wasted time and money. After the rough weather ends, it's wise to give your roof a quick check-up to insure that your home is protected.

Leaking roof systems can result from several sources. The most common include cracks in flashing around the chimney and vents, worn out or missing shingles, or condensation from inadequate attic ventilation. Here are some warning signals courtesy of GAF Materials Corp. that your roof may be costing you money and leaving your property vulnerable.

Warning sign: dark, "dirty-looking" areas on roof
Possible cause: Environmental pollutants; vegetation, fungus or algae; loss of granules due to shingle age.
Warning sign: missing, cracked or curling shingles
Possible cause: shingles at the end of their useful life.
Warning sign: leakage in attic after driving rain
Possible cause: leaky or inadequate shingle underlayment or deteriorated flashing.
Warning sign: roof shingle, sheathing and siding decay
Possible cause: poor attic ventilation.
Warning sign: blistering/peeling of outside paint
Possible cause: excessive temperature or high humidity due to poor attic ventilation.
Warning sign: stains on interior ceilings/walls or mold and mildew growth
Possible cause: inadequate or faulty shingle underlayment allowing leakage or inadequate ventilation.
Warning sign: excessive energy costs
Possible cause: insufficient attic ventilation allowing heating/cooling system to run excessively.

If you notice any of these warning signs, do something about it. Many people neglect their roof or think roofing installation is simple. A well-installed, well-maintained roof is one of the most important things you can do for your home.

Consider using a professional roofing contractor to fix your problems. Don't hire just any contractor to perform repairs or replace your roof. Beware: Roofing is one of the top reasons for complaint calls to the Better Business Bureau. Look for an established contractor, one with a track record he can prove.