Q&A / 

PVC Pipe vs. Cast Iron Pipe

Cast iron piping has not given up the ghost. Many homeowners associate cast iron piping with antiquated plumbing that is prone to developing leaks. Often people think that it clogs quite easily. Conversely, many people think that modern plastic PVC plumbing piping is the miracle material. Well, both materials have advantages and disadvantages. Let's talk about both types of pipe and see what you think.

That Old Black Metal

Cast iron piping has been used successfully in plumbing systems for hundreds of years. In fact, in the year 1623 cast iron pipe was installed in the Fountains of Versailles in France. That same piping is still functioning today. Thousands of miles of municipal water and sewer systems use cast iron pipe. The reason is long term durability. Cast iron simply lasts.

Virtually every residential home built prior to 1960 had some form of cast iron piping in its drainage system. The primary drainage stacks or pipes within the walls were constructed of cast iron. The branches off of these stacks which connected to sinks, toilets and tubs often used lead piping or galvanized pipes. Galvanized iron piping is especially prone to clogging. I have personally removed hundreds of these pipes which connected to kitchen or bathroom sinks. In virtually every instance, these pipes were clogged solid.

However, the cast iron stacks only two to three feet away from the sinks were completely free of obstructions. Unfortunately, many people don't realize this phenomena and brand the cast iron as a poorly performing product.

Cheap Labor & Cast Iron

Years ago, residential construction labor costs were insignificant. Time was not always an issue with respect to how long a particular task took to complete. For example, imagine how long it took to nail on those thin lath boards which allowed plaster to be applied to the walls and ceilings of houses. Think of the amount of time it took carpenters, using hand tools, to mortise hinges and locks into doors. The same is true for old style cast iron piping.

Old style cast iron piping was a chore to install. The plumbers had to pack oakum into each joint and then pour molten lead to seal the joint completely. This lead joint was then hammered to finish the job. The job of installing cast iron was tough, time consuming and dangerous.

Modern Methods

The cast iron pipe available today looks somewhat similar to old cast iron. However, the methods of installing the material have changed drastically. Gone are the oakum and molten lead. In their place you now find vulcanized rubber seals and stainless steel band clamps.

Cast iron piping systems can now be installed in a fraction of the time it took to install them 50 years ago. In fact, modern cast iron piping can be installed just as quickly as plastic PVC piping.

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2 Responses to PVC Pipe vs. Cast Iron Pipe

  1. I'm in the process of cutting out and replacing some rusty, leaky cast iron pipes that are clogged solid, so the assertion that they are somehow clog proof doesn't add up.

    • Well, perhaps they're full of grease or they were abused. The point I was trying to make is that cast iron has a rich history of not producing expanding scale on the inside of the pipe like galvanized iron.

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