How to Safely Remove a Cast Iron Vent Pipe

Access the situation at hand before gathering materials: if the cast iron is exposed, meaning you can clearly see where the pipe enters the home and leaves, some of the harder elements of the task are already complete. If the pipe is encased behind brick or drywall, common with older stoves that featured cast iron piping, you’ll need at least a 10-pound sledgehammer to handle masonry work or a drywall saw to cut through the wall. Gather the appropriate materials, including safety gear -- goggles, gloves and ear protection if desired -- for all involved in the project.

Lay a drop cloth flush to the wall to catch debris. Start at the top of the wall and hammer into the brick or saw into the drywall. For brick, bust enough brick so that they’re loosened enough to remove by hand; for drywall, saw away small incremental sections to expose the pipe. Skip this step if the pipe is already exposed.

Look at the pipe in the wall once you have a clear view; in nearly all cases there is some kind of wood or metal bracing system that anchors the pipe to the wall. Feel each brace and wiggle them slightly to check their integrity but don’t pull or jerk hard -- you might send the pipe crashing down where people can get seriously hurt. If you don’t trust the current bracing system, use bands of wood or metal slats and an electric screwdriver to screw in a new bracing system over the top of the old one.

Open the cleanout at the bottom of the pipe and stuff a handful of clean rags in to catch debris from cutting the pipe. Use a tape measure and a marker to mark off incremental 36-inch sections on the pipe. You’re going to be cutting the pipe and removing it in sections; by doing so, you make each cut section -- which weigh around 30 pounds apiece -- manageable.

Use a snap cutter -- a chain-based saw that can be rented at many home improvement stores for around $20 an hour -- to cut through each marked off section, beginning at the top and working your way to the bottom, removing braces as you go. As you cut each section, work slowly to avoid possibly shattering the pipe into shards and remove each cut section. Realize this is a time consuming effort and you will likely have to swap the old chain-blade for a new one.