Storm Collar

Think of the storm collar as an upside-down funnel. It’s fastened around the chimney pipe and sealed at the top with a high-temperature sealant suitable for chimney pipe. Its lower edge flares out over the top of the flashing cone or the raised collar on the rain pan. Water running down the pipe hits the storm collar and is directed outward, onto the flashing and off the roof, instead of into the gap around the pipe.

Because the storm collar isn’t fastened to the flashing, the pipe can still move up and down as it heats and cools while the gap stays covered.

• Water dripping around the fireplace or stove after rain
• Water stains on the ceiling around the chimney pipe
• Rust streaks on the chimney pipe below the collar
• Cracked, peeling, or missing sealant at the top of the collar
• A collar that has slid down, tilted, or come loose
• No storm collar at all where the pipe meets the flashing or chase top
• Rust or water marks around the pipe inside the chase or attic

1. Inspect. We check the storm collar, its sealant, the flashing or rain pan, the chimney pipe, and the cap. Leaks around a metal chimney often involve more than one of these.

2. Reseal or reposition. If the collar is in good shape, we clean off the old sealant, set the collar at the right height, tighten it, and reseal it with a high-temperature sealant suitable for chimney pipe.

3. Replace. Rusted, bent, or wrong-size collars are replaced. On factory-built chimneys, we use the storm collar listed for that chimney system, because manufacturers design these parts to fit their pipe and clearances.

4. Check the rest of the top. We make sure the cap, flashing, and chase cover are sound so the whole chimney top sheds water properly.

A storm collar is a small part compared with the damage a slow leak can cause. Water that runs down past the flashing or into the chase can rot roof decking, framing, and insulation, cause mold, rust the chimney pipe and fireplace, and stain ceilings. Because these leaks are hidden, they often go unnoticed until the damage is significant. Checking the storm collar is a standard part of inspecting any metal chimney. If you’re dealing with an active leak, see chimney waterproofing and leak repair.