PVC into cast iron

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by blue96bird, Apr 3, 2006.

  1. blue96bird

    blue96bird New Member

    Apr 3, 2006
    I am replumbing a bath and was told by my local plumber the you are not supposed to thread PVC into cast iron. The 4" stack has a 1 1/2" threaded hole where the old galvanized sink drain was joined and a previous plumber unscrewed the galvanized and threaded PVC into it. The threads look like they match, and it has been in place for 10 years and is not leaking.

    If this is not proper, what is the proper way to transition this?
  2. plumber1

    plumber1 Plumber

    Aug 7, 2005
    Some fellas like to screw pvc to cast iron or galvanized.

    Personally I like to connect them with no-hub bands. I've seen the pvc come loose and I blamed it on hot water. Steel and pvc expand and contract at different rates.
  3. Sponsor

    Sponsor Paid Advertisement

  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    If the cast iron has a proper 1 1/2" thread, not a hole drilled and tapped, then there is nothing wrong with screwing the PVC into it.
  5. blue96bird

    blue96bird New Member

    Apr 3, 2006

    It does have a proper 1.5" thread. I believe he wanted to replace those drains to pad the bill. I can see replacing the lead closet bend on the first floor and the lower half of the stack going to the basement, but not all of the drains on the second floor too.

    BTW, it is a remodel and the walls are gutted to the studs.
  6. Cass

    Cass Plumber

    Nov 12, 2005
    If everything is open and the drains are galvanized I would recomend their replacement also.

    My recomendation would not be so I could "pad" the bill.

    It only makes sense based on all the clogged/rusted out galvanized lines I have replaced over the years and it's only a matter of time B4 they will need to be replaced.
Similar Threads: cast iron
Forum Title Date
Plumbing Forum, Professional & DIY Advice Cast Iron Pipe with odd size advice Sep 14, 2017
Plumbing Forum, Professional & DIY Advice Replacing cast iron and moving lines Sep 9, 2017
Plumbing Forum, Professional & DIY Advice 3" ABS to 4" cast iron- will I regret how I did this? Sep 4, 2017
Plumbing Forum, Professional & DIY Advice Tying into cast iron soil stack by drilling hole Aug 25, 2017
Plumbing Forum, Professional & DIY Advice Old toilet flange flush with floor on cast iron Aug 5, 2017

Share This Page