The Importance of Chimney Flashing


Chimney flashing usually goes unnoticed until it fails. Flashing surrounds the base of your chimney to keep water from leaking in where your chimney structure meets your roof. When chimney flashing fails, water can seep in around the chimney, resulting in ugly ceiling spots, wavy wallboard, peeling wallpaper, and the rotting of your home’s joists. So how do you know if your chimney flashing will keep your home safe from water damage?

Proper chimney flashing installation

Many roofers, builders, and masons can rush the installation of chimney flashing, failing to follow the steps of proper installation and potentially leaving your home susceptible to water damage. When installed properly, chimney flashing features two layers. First, a layer of L-shaped metal is woven into your chimney’s shingles, with one side lying flat against your roof and the other side flat against your chimney. To completely seal the flashing, another layer of metal flashing is embedded into your chimney’s masonry with mortar, and then the metal is folded down over the bottom layer of flashing to keep water out.

Types of chimney flashing

There are several materials used for chimney flashing, and the type of metal used will affect the longevity of your flashing. In the north, lead is commonly used as flashing because it molds easily around corners. On higher-end jobs, homeowners will opt for stainless steel or copper, which won’t rust, corrode or develop holes like other flashing materials can. Copper has the added benefit of being able to be soldered at the corners, while other metals would form seams that need to be caulked to keep water out. Caulking is often the first thing to fail in the flashing, letting water into a home.

How to tell if your chimney flashing is secure

Unfortunately, the first sign that there’s a problem with chimney flashing is often a water leak. If you don’t want to be surprised by an ugly spot on your ceiling or discolored or warping wallboard, it’s worth having your chimney flashing inspected. You can ask your chimney sweep about the state of your chimney flashing during your annual inspection. Knowing that your chimney flashing is improperly installed or starting to corrode can help you address the flashing before it causes a problem in your home.

What to do about bad flashing

If your chimney flashing is already failing, or if it’s improperly installed or starting to break down, don’t wait until you have major water damage to have it fixed! Chimney experts are generally the best option for repairing faulty flashing, as roofers may often band-aid the issue and fail to resolve the problem. If you need to have your chimney flashing inspected or repaired, call Your Chimney Sweep to schedule an appointment today!