3.5-inch (?) Cast Iron Drain Pipe


Old 01-21-11, 07:40 AM
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
3.5-inch (?) Cast Iron Drain Pipe

I am remodeling a bathroom in my 1949 slab-on-grade house in Arizona and am moving all the fixtures. The existing sub-slab sewer is cast iron pipe with an inside diameter of approximately 3 5/8 inches and an outside diameter of almost exactly 4 1/4 inches. I have measured it in several locations. It appears to be 3 1/2 inch (nominal) pipe. I need to cut out sections of the cast iron and add fittings for the new fixtures. Does anyone know of a supplier of replacement pipe (preferably PVC or ABS) and hubless connectors?
Sponsored Links
Old 01-21-11, 11:49 AM
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
It may be metric-size pipe (ID of 92 mm and an OD of 108 mm).
Old 01-22-11, 06:41 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 2 Votes on 2 Posts
Metric in 1949??? I doubt it. We had not been infiltrated with such stuff back then. We were American size standard. Not sure why the difference in size, but you should be able to use a 3" to 4" Fernco fitting with worm gear clamps to join the pipe you have with a new 3" PVC. The fernco will stretch somewhat, but not sure if your installation will allow it or not.
Old 01-22-11, 08:10 AM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 17,806
Received 14 Votes on 12 Posts
What you need is a no-hub. This is what most codes require. A no-hub has a stop inside that lets you butt it up to the pipe. And for fitting cast iron to pvc you need a no-hub, but its called a mission coupling. Cast and PVC are two different sizes and on the mission coupling one side is larger then the other internally. Not like a bell coupling.

Here is the link look under 4" x ??? 3"x ???. Whatever you want to fit.

Mission Rubber Products.html

Mission Rubber Products.html

Mike NJ

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes
Ask a Question
Question Title:
Your question will be posted in: