Installing a Chimney Top Installing a Chimney Top

What You'll Need
Drill
Masonry bit
Tapcon screws
Chimney top
Heat and water resistant silicone
Phillips head screwdriver

A chimney top or chimney cap is a device which is designed to allow smoke and ash to flow out but prevent animals such as birds, bats and squirrels from entering. Many of these animals will even go as far as to build nests in the chimney flue if given the opportunity. A chimney top will also help to keep rain water from entering your chimney.

Step 1 – Materials

If you have a concrete chimney that does not contain an exposed metal flue, you will need tapcons to anchor the top to the chimney. Purchase a masonry bit to pre-drill the concrete.

While silicone is not necessary, it can provide extra protection. When selecting silicone for a chimney, verify that it has a heat rating of at least 1500 degrees and that it is waterproof.

Step 2 – Safety

Nearly all chimney tops are made of sheet metal. This works well because it is both lightweight and durable, though it can have sharp corners. Wear a pair of heavy leather gloves to protect your hands while working.

Step 3 – Determine the Type of Chimney Top You Have

The most common type of chimney top is cut to the size necessary to fit on the outside of the chimney flue. The other style is installed inside of the chimney, so it is cut to fit the inside of the flue.

Step 4 - Installing External Chimney Tops

Mount the chimney top on the flue until it is securely covering the entire flue. There should be a total of 8 self-tapping metal screws supplied with the top. Screw each one into a corner of the chimney top until it is tight.

For added water protection, you can apply a thin strip of heat and water resistant silicone to the bottom gap.

If your chimney does not have an exposed metal flue, you will need to pre-drill the chimney with a masonry bit and use tapcons in place of the self-tapping screws.

Step 5 – Installing Internal Chimney Tops

Slide the chimney top into the chimney flue. It should be relatively tight, so it will take a bit of effort to get it fully seated inside. Once the top of the base on the chimney top is flush with the top of the flu, apply heat- and water-resistant silicone around the entire flue. This will help prevent water from getting inside.

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