Cast-iron pipe has been around for hundreds of years, and had been the pipe of choice for many plumbers since
indoor plumbing began. The first uses of cast-iron pipe is unknown, but is dated at least back to the 14th and 15th
centuries. It can only be imagined that some of these early pipes would have found their way into water uses. It is
hard to tell exactly when cast-iron lines found their way into american homes, but they were instrumental in the
development of modern plumbing systems.
Cast-iron's main use in US homes that are still in use is for drains. It was the best choice for drains until the
invention and distribution of pvc and still has uses in larger cities and locations subject to severe damage, where
pvc may crack or break.
Pvc rules the residential building world these days due to it's price and simplicity(it's weight too!). Pvc also
has a longer life span in these conditions. Cast-iron will corrode on the inside of the pipe, often getting very thin
in places. A crack opening up the length of a piece of pipe length-wise(presumably at the seam) is very common. At the
same time, many other pieces that were all part of the same installation will appear to be just fine.
It's generally considered a good idea to remove as much cast-iron as possible these days, but it's not as much of
a problem as galvanized drains can cause.
Repair and working with cast-iron
Originally, cast-iron was connected by means of filling a joint with molten lead. This is a whole procedure in itself.
The original procedure is rarely, if ever, used anymore but if required, needs to be done by a plumber. There is also
another way using the same type of filler, called oakum, and then filling the joint with a paste-type sealant that will
The most common method of dealing with cast-iron is to remove the damaged pieces, then attach new pvc to it using a
fernco adapter. The cast-iron pipe needs to smooth and often isn't, so filing or grinding rough areas is sometimes
Cutting cast-iron is probably the most difficult part. Most plumbers should have a cutting tool for cast. There are
several versions available, with varying degrees of effectiveness in certain circumstances. A reciprocating saw is
a possibility, but be prepared to be cutting for a while and using a few blades. A grinding tools works very fast, but
depending on the type that is used, it may be difficult or impossible to get all the way through or around it.
Supporting the pipe prior to cutting is extremely important given the heavy weight of cast. Most cast-iron work
is probably best left to a professional