What Size Chimney Cap Do I Need?

Tools

• When you want to go measure your chimney for a chimney cap, you need a measuring tape and a ladder that allows you to access the chimney itself. This does involve getting on your roof, which can be dangerous if you are not careful. If you are uncertain about climbing up on your roof yourself, call a roofer or any other professional equipped to handle the task for aid.

Round Chimneys

• If your chimney has a round shape, you typically only need one measurement. Measure from side to side across the top of the chimney. Essentially, you want the diameter of the chimney going from outside edge to outside edge.

Rectangular and Oval Chimneys

• If you have a rectangular or an oval chimney, measure the length and the width of the chimney across the top of the chimney. For an oval, measure at the longest and the widest points possible.

Double Wall Chimneys

• A chimney with a double wall should have a cap that fits to the inner wall, but a roof that extends to cover the outer wall. Measure the inner wall for the cap measurement and then measure the outer wall to figure out the minimum measurements necessary for the roof.

Considerations

• The mesh portion of the chimney allows the chimney to vent properly. Make sure that no matter what chimney cap you buy that the mesh portion rises at least 5 inches above the chimney’s lip. This ensures that your fireplace and your chimney function properly.