Do You Have Chimney Flashing to Prevent a Leak?

Water spots on the ceiling are not just an eyesore; they are also a warning sign of water intrusion. A leak in your roof can cause a wide range of problems from toxic black mold to hundreds of dollars worth of ruined dry wall and structural beams.

Homes with chimneys are more susceptible to leaks. In many cases, the culprit of a leaking chimney is bad or missing flashing.

What is chimney flashing?

Chimney flashing is what connects your chimney to the roof. When a home is built, a gap is left between the roof and the chimney to protect the combustible materials of the roof from the high temperatures of the chimney system. The gap also protects the roofing material from stray sparks that might fly out of the flue and ignite it.

Flashing is a non-flammable, waterproof seal that prevents rain and snow from slipping through that gap into your home. Without flashing, water could freely pour into your home ruining walls, ceilings and structural beams.

What is flashing made of and how is it installed?

Flashing is usually made of sheets of aluminum or galvanized steel. In some cases, it is made of coper. When it is installed properly, there are two layers of flashing: step flashing and counter flashing. The first layer, called step flashing, is made up of L-shaped sheets of metal that are woven into the roofing shingles. The second layer, called counter flashing, is embedded into the mortar joints in the chimney and then folded down to cover the step flashing. High urethane caulk is used to seal the corners.

How can you tell if your chimney flashing needs to be replaced or repaired?

Though flashing is made to be durable, overtime it will wear out. Water can get into your home if the caulking falls, the seams come apart or the flashing corrodes.    

If the flashing on your chimney is visible from the ground, it is smart to look at it periodically for signs of rust, loose pieces of caulk and gaps between the two layers of flashing. Unfortunately, most flashing is not visible from the ground. Many homeowners don’t realize that there is a problem with their chimney’s flashing until they notice damp spots on the ceiling or walls around the chimney.

The best way to prevent water damage from a leaking chimney is to schedule an annual chimney inspection. The National Fire Protection Association recommends a yearly inspection to make sure that there is no internal damage to your chimney system that could cause a house fire or carbon monoxide poisoning. A CSIA-certified chimney sweep will also check the exterior of the chimney to make sure that there are no pathways for moisture to enter your home or the chimney system. That includes inspecting the chimney flashing to ensure that it is not missing, worn out, corroding or poorly installed. Scheduling an annual inspection could save you from a big headache and expensive repairs.

If you suspect that your chimney is leaking, you should call an expert right away so that the problem does not spread or cause extra problems!

Whether you are concerned about a chimney leak or need an annual inspection, our chimney experts are here to help you. Give us a call if you’re located in or around New York’s Hudson Valley!