A chase cover is important part of a chimney, it is typically a metal cap that seals the top of the chimney from water, debris, and animals from entering the chimney. They are typical of pre-fabricated and sided chases. They are sometimes seen on older masonry chimney as an added protection from the elements.

Does the Type of Metal Matter?

Most chase covers that come with prefabricated fireplaces are sometimes made with thin, inexpensive galvanized steel or aluminum and often installed incorrectly due to the rush of building newer properties. A galvanized cover will often begin the rust after a few years. The issue with rusting is it will often occur near the screws and nails that attach the chase cover. As well as pooling in any areas that sink. When this occurs, water can penetrate your chimney and cause performance issues, mold or structural issues over enough time. Aluminum covers do not rust, but because aluminum is typically flimsy metal it can bend or crack under the weight from snow. There are signs to look for that your chimney sweep should look for during the annual inspection.

Rusting on the chase

Rust on the cover where water is pooling

Rusting around the nails or corners of the cover

Cracks or holes in the cover

If you chimney shows signs of water damage inside the chimney, the cover may not be

effectively working

Water inside of your fireplace or smoke chamber

Missing or cracked mortar.

The best metal to use is going to be stainless steel or copper. The difference in effectiveness between them is going to aesthetic. Using a well-made chase cover is going to provide your chimney the protection it needs to effectively withstand the elements. To see if you need your chase cover replaced, contact your local chimney sweep.