Do You Need a Chimney Cap?
Here is the deal. A new chimney may not need a cap. But over the years branches grow over the roof and block the draft. Rain falls straight down the flue. Birds move in and nest. A cap fixes all three problems.
The Hood
It stops downdraft. It also stops direct rain from going down the flue and hitting the bottom of your fireplace.
The Screen
It stops birds and critters from getting in and nesting in your chimney.
The Flange
It sits right on top of the clay liner that pokes through the roof. Screws in each corner hold it tight and you are good to go.
Materials. Galvanized steel with a black powder coat is the standard option. Stainless steel is the premium option and it lasts longer. Copper is the upgrade and it looks great.
Sizes. Most homes have standard sizes. One for a fireplace flue. One for a furnace or boiler flue. These two flues often run side by side up the same chimney. But sometimes the flues sit too close together. Then the hoods bump into each other and standard caps do not fit. That is when you need a custom cap. A multi flue cap bolts into the concrete crown. Undo four bolts and you can lift the hood to clean the flue.
What about a flue you no longer use? Cap that one too. It stops heat loss from your home. It stops birds and insects. It stops leaks. But do not seal it shut completely. A flue needs a little airflow, or moisture builds up inside. A proper cap gives you protection plus a little ventilation. Never just balance a slab on top and call it done.
