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  1. #1
    Join Date
    Jan 2009
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    Cool Replacing copper drains

    My house was built with 1.5, 2.0 and 4.0 dia copper drainpipe in the walls and 2.0 & 4.0 dia cast iron pipe through the basement floor. after several leaks I would like to replace the copper with plastic, although there may be sound issues. My question are:
    1) How do I join the plastic to the cast iron that is just above (1/4") the concrete floor in the basement?
    2) What is the better plastic product to use?

  2. #2
    Join Date
    Aug 2007
    Location
    The Great White North
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    4,045

    Default Re: Replacing copper drains

    Quote Originally Posted by Jack02 View Post
    My house was built with 1.5, 2.0 and 4.0 dia copper drainpipe in the walls and 2.0 & 4.0 dia cast iron pipe through the basement floor. after several leaks I would like to replace the copper with plastic, although there may be sound issues. My question are:
    1) How do I join the plastic to the cast iron that is just above (1/4") the concrete floor in the basement?
    Any time when dissimilar materials are joined with cast iron ( CI ) a transition coupler is used .
    Here is a link that generally describes what those are and how to make the connection .... http://www.rd.com/19566/article19566.html

    Being sight unseen ........ If you only have a 1/4 inch of the cast iron pipe sticking out of the concrete then you will likely need to carefully break the concrete around the pipe exposing enough to fit the coupler.




    2) What is the better plastic product to use?
    Either the white PVC or the black ABS are equally as good and usually are a regional preferance .... around here ABS is pretty much exclusively used.

    With PVC you need to use a primer/cleaner on all joints before applying the adesive which is a 2 step process.
    Whereas the ABS doesn't require any primer ..... simply apply the adhesive .... 1 step process which makes it easier to use.


    Hope this helps.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
    Join Date
    Jan 2008
    Posts
    731

    Default Re: Replacing copper drains

    Quote Originally Posted by Jack02 View Post
    My house was built with 1.5, 2.0 and 4.0 dia copper drainpipe in the walls and 2.0 & 4.0 dia cast iron pipe through the basement floor. after several leaks I would like to replace the copper with plastic, although there may be sound issues. My question are:
    1) How do I join the plastic to the cast iron that is just above (1/4") the concrete floor in the basement?
    2) What is the better plastic product to use?
    There are other approved methods for the transition. Your options depend on your plumbing and building codes and any local ammendments. Your first best step is to contact your local office and inquire as to the codes in effect in your area.

    The old method of packing hubbed CI to ABS stack with oakum and topping with lead is no longer done usually. There are special sealants used in stead of molten lead. Sometimes oakum still used to pack the joint for the transition, sometimes alternative products are used. Many areas specifically prohibit the use of an exposed elastomeric coupler used on a verticle main waste stack.

    You speak of replacement of the entirely or near entirety of your DWV from main sewer to vent.

    Plumbing codes and local authority would control as to if this change of materials an percentage of work constitutes maintenance, repair, but more likely not and you may be required to make changes which bring the system up to current code standards. Work of this nature and extent may likely require permit (with description of work and possibly drawings and calculations/specifications for the engineering) and inspections. Replacement will likely require some re-engineering - with careful attention to venting, pitch, drain flow units, sizing, etc. Some areas allow a homeowner to complete these tasks, some areas require work of this nature be done only by a licensed plumbing contractor or licensed pipe fitter. You should check this out first and foremost.

    ABS expands, contracts, moves less with temperature changes than PVC, however in many areas ABS is not allowed to use above earth due to it releases deadly toxic gas when it burns (cyanide IIRC), and when it decomposes over time it tends to puff up from the inside and clog/brittle/break. PVC moves significantly, expands/contracts with temperature changes. Hubbed Cast Iron is the quietest and will last longer but is heavy, expensive and requires skills to install correctly.

    All plastic pipes and fittings are not the same - you would need to use the correct sanitary fittings not vent pieces (for example a vent tee v. sanitary tee, or an elbow v. a bend). You would likely need a section of verticle and a sanitary piece to provide for a cleanout at the stack. If our home is presently "wet vented" you might be required to redesign the entire system.

    P.S. Many codes prohibit or limit the number of connections/junctions of ABS to PVC (or other dissimilar materials within the DWV system) in residences - for example limiting to one transition, or one solvent welded transition for the entirety of the Drainage/Waste portions of a DWV residential system within the living unit. Some areas of jurisdiction prohibit the use of an elastomeric band coupler in enclosed ares above ground, limiting to exposed areas (not enclosed by walls, ceilings) and/or direct burial. Consider that your under the basement floor might not even be CI there are/were other hubbed materials that may have been used like transit pipe for example.

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