Identification

• Water can seep into your attic, cause structural damage and make insulation less efficient. Leaks around vents or chimneys are common in many homes, especially as they age. Moisture and air are brought into the warm space of your attic through gaps around the chimney on the roof. Gaps and spaces around your chimney do not have to be large to be a problem, as air leaking into your attic also causes moisture problems. Eliminating all gaps around your chimney and roof is the best way to control attic moisture.
  
  

Signs and Symptoms

• When moisture is present in your attic, it can cause damage, such as wood decay, to the structure of your home. While attics are ventilated to remove excess moisture that comes inside, constant moisture or severe water leaks can cause wood to become dry and brittle. Eventually, the wood inside your attic may crumble and require repair. Damp insulation is another sign of water leaks and excess moisture inside your attic. Mold may begin to grow when leaks are not repaired and water continues to seep inside. Once moisture is present, mold can begin to grow in as little as 24 hours.
  
  

Causes

• Most chimney leaks are caused by the degrading of materials as the home ages. Furnace cement is often used to seal the areas around the chimney on the roof and will eventually dry out. Once furnace cement begins to dry out, it becomes brittle and cracks easily, causing a gap around your chimney. Missing or damaged shingles around your chimney can also cause water to seep inside your attic. Flashing is sheet metal used to waterproof your roof around the valleys, hips and angles around the chimney. If this flashing is defective, water leaks can occur.
  
  

Solutions

• Inspect your roof around your chimney to determine the source of your water leak. Damaged or missing shingles can be replaced by most homeowners. Apply furnace cement or high temperature caulk around your chimney to seal small gaps near the roofline. Replace any narrow or defective flashing around your chimney and the valleys on your roof. Homeowners inexperienced in roof repairs or those who have large leaks may wish to hire a roofing contractor to repair the leak. After all leaks are repaired, inspect your attic for signs of wood rot or mold growth. Replace any damaged wood and clean any visible mold. You can scrub mold away with liquid dish detergent and water. Dry thoroughly when all mold is gone. Replace any soggy insulation to be sure your home is insulated properly.