Flue Issues in a Wood Stove With a Metal Roof

Mounting Brackets

• While brick chimneys and cement-block chimneys are largely stand-alone structures that require nothing more than bracing, flues for wood stoves need to be bracketed in place, as they work their way up the wall and then eventually out through the roof. With a metal roof, ensure you use the proper brackets to mount the flue to the metal of the roof; use galvanized brackets, or some other form of non-rusting brackets, so they'll last.

Roof Stability

• Metal roofs are often installed in sheet format, such as with tin. Unfortunately, when people cut out the holes in the metal roof for the flue running up from the wood stove, the screws mounting the roof sheets of metal can be loosened. If this happens and high winds occur, it will rip the tin off the roof and the flue along with it, since the flue is attached via brackets to the metal sheets. Always ensure that the sheet metal is firmly screwed in place when cutting, before mounting the flue.

Installation

• The installation of the flue is also important, and while some homeowners think they can simply cut a hole, run the pipe, mount the brackets and go on about their business, it's important to follow the manufacturer recommendations precisely -- to ensure you're covered by warranty and insurance. Flues require flashing as well as fireproof caulking, and you have to use the proper types for the flue to bond with the metal. Different metals and flues have different requirements, so always check with the manufacturer before purchasing installation supplies.

Overall Rusting

• The most prevalent issue with flue pipes to metal roofs is rusting. This is especially true with treated roofs that aren’t cut in a proper manner. Shears are needed to ensure the protective coating isn’t burned off. If the roof begins to rust, it will transfer that rust to the flue, which in turn weakens the flue. Likewise, if the wrong brackets are used and they begin to rust, this will transfer to the flue. In addition, if the proper flashing and caulking aren’t used, the resulting water will cause rusting down the flue pipe to the stove.