"Every winter a large volume of ice builds up around our house’s wood framed chimney chase. Over the winter the ice volume keeps increasing, hanging in sheets from the eaves on both sides of the chase. What’s happening?"

Probably your wood framed chimney chase is attached to the outside wall of your home near the eave of a roofline. The most common cause of this problem is a lack of insulation and vapour barrier on the inside of the framed chase. These walls should be insulated the same as any exterior wall.

The hot air from the metal chimney inside this chase is probably escaping into the adjacent attic space, melting the snow on your roof. This melting snow is then freezing as it travels down the unheated eaves at the sides of the chimney chase forming sheets of ice.  If your chimney chase is large enough, you may be able to insulate it by either removing the top chimney “lid” or the “soffit” on the under side. Install as much insulation as the framing will permit. Be sure to insulate the space between the chase and your attic also. Keep the insulation at least 2 inches clear of the metal chimney vent and install a vapour barrier on the warm side of the chase walls. Keeping the chase warm will also ensure that the hot flue gases in the metal chimney will exit the chimney quickly. This should correct the problem.