A chase cover is a metal covering designed to keep elements like rain and snow, from entering the home via the chimney chase.
Over time almost all non stainless steel pre-fab chimney chase covers rust due to the elements. Snow, ice and rain gets trapped on top of your chase cover and starts the decaying process. Leaves and pine straw also mixed with the moisture creates an acidic condition and breaks down the galvanized coating.
When this breakdown occurs the chase cover begins to pit. This will allow water to drip inside your chimney. Let this rust stain be your sign that it is time to replace your chase cover.
It is recommended when replacing your chase cover to use stainless steel. Stainless steel is more durable, stronger and will look new for a longer period of time. It is also recommended that it be designed with a cross break which creates a “dome” effect. This will prevent the snow, ice and water from pooling on top of your cover. Stainless steel chase covers may come with a lifetime guarantee against rust and corrosion.
If you want to protect your home from water damage it is highly recommended that you inspect the chase cover and if in an undesirable state, replace it immediately.