How to Take Apart Cast Iron Plumbing
Cast iron pipes are commonly found in older homes and also as primary drainage or sewer lines in homes built into the 1980s. Although threaded cast iron pipes were available for lines up to 2 inches inside diameter, the more typical cast iron piping used bell-shaped connection fitting, referred to as a "spigot," that was packed with a fibrous yarn, called "oakum," and then sealed with molten lead. Dismantling cast iron plumbing pipes follows a basic procedure that disconnects the sections for easy removal.
Access a connection location in the cast iron drain. Drill sequential holes into the lead seal around the mouth of the over-fitting of the pipe section using a 3/8-inch bit in an electric drill. The lead seal is usually only an inch or so deep and drilling holes about 1/2-inch apart around the seal will break it into smaller pieces.
Pry out the separate pieces of lead seal using a screwdriver. Tap the pieces with a hammer and screwdriver, if necessary, to break the lead away from the pipe surface.
Pry out the oakum that is stuffed into the pipe fitting to block the lead seal using a screwdriver.
Cut into a span of cast iron pipe, if necessary, to remove a threaded section of cast iron pipe using a chain cutter. Wrap the chain of the cutter around the pipe and feed it through the cinch ratchet until the chain is tight to the pipe surface. Use an adjustable or socket wrench to continue tightening the chain cinch until the pipe snaps under the chain.
- Cast iron plumbing pipe is heavy, even in shorter sections. Its recommended that you enlist a helper in dismantling cast iron piping as described in this procedure.
- Older lead seals in cast iron pipe may be brittle and chip while being drilled or removed. Eye protection should be worn during this project.
Paul Massey has been writing since 2009, drawing on a 35-year career in the construction industry. His experience includes 15 years as a general building contractor specializing in architectural design, custom homes, commercial development and historic renovations.