Q&A / 

Cast Iron Drain Pipe

cast iron drain pipe

Cast Iron Drain Pipe | Here are the four common sizes of cast iron drain pipe you'll use in your home. Left to right: 4, 3, 2, and 1 1/2 inch. You may not know WHY and WHERE you should use cast iron drain pipe. That's why you should do a fast plumbing code consult. Copyright 2019 Tim Carter

Cast Iron Drain Pipe - Quiet, Durable, and Wonderful

"At the very least, use cast iron drain pipe for your toilet pipes across ceilings and down walls. This will stop embarrassing noise and add value to your home."

Tim Carter | Founder - AsktheBuilder.com

Modern cast iron drain pipe is nothing like the cast iron pipe poured into molds years ago. The wall thickness is consistent and the cast iron can last hundreds of years.

It's important to realize that you don't have to use it for all the pipes in your home. Toilet stacks that make noise are the first place to use cast iron.

All vent pipes in your home can be normal cellular PVC pipe to save money. Vent pipes just have air move through them.

You can also use PVC for the horizontal branch arms that extend left or right of a vertical stack for any common sink. Look at this photo of branch arm and WATCH the video below to see a video of several branch arms serving sinks:


This is a great example of how to mix PVC and cast iron to save money. You can see the cast iron vertical stack coming up through the floor. It's for a master bathroom vanity. It switches over to PVC and goes up another 14 inches to the branch arm that will connect to the sink p-trap in the vanity. All the other PVC pipes in the photo are vent pipes that only have air in them and some tiny amount of liquid condensate. Even the large 3-inch PVC pipe is a vent pipe that will extend up and through the roof.

Related Links

PVC vs Cast Iron - And the Winner Is!

Replace Cast Iron with PVC? - Not So Fast!

Cast Iron is Quiet and a Breeze

How Do You Connect the Pipes and Fittings?

You use no-hub stainless-steel couplings that contain a rubber seal and a massive stainless-steel outer band. Two ring clamps squeeze the rubber against the cast iron to create a leak-proof connection. The couplings allow you to make adjustments for perfect alignment.

Here are some of these couplings in this photo. I installed all this cast iron in my daughter's new home in the winter of 2019.

cast iron drain pipe residential

This is modern cast iron drainpipe for a residential house. It will last for centuries and is QUIET. the stainless-steel couplings have a rubber boot that each end of the pipe fits into. You tighten the two clamps and a leakproof seal is created.

Free & Fast Bids

CLICK HERE to get FREE & FAST BIDS from local plumbers who can install cast iron.

Does Cast Iron Pipe Pass Code?

Yes, the cast iron pipe is code compliant. It's used exclusively in large high-rise and institutional buildings because it's durable and fireproof.

Does Cast Iron Pipe Burn?

No. Cast iron pipe will not burn. Burning PVC plastic pipe creates toxic smoke and gas that can kill you in seconds should you breathe in the fumes.

Why is Cast Iron Quiet?

Cast iron pipe is much denser than PVC. The water crashing down a vertical stack doesn't have enough energy to make cast iron vibrate. However, PVC will vibrate readily like a bass drum in your walls and ceilings.

Cast Iron Drain Pipes - Quiet, Durable & Practical | AsktheBuilder.com
Article Name
Cast Iron Drain Pipes - Quiet, Durable & Practical | AsktheBuilder.com
Cast iron drain pipes are fantastic. Modern no-hub cast iron is spun cast and smooth. Just use it if you have to for toilet stacks to cut down on NOISE.
Publisher Name
Publisher Logo

One Response to Cast Iron Drain Pipe

Leave a Reply

Your email address will not be published. Required fields are marked *