Plumbing question- PEX

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by new_home_owner, Jun 29, 2009.

  1. new_home_owner

    new_home_owner New Member

    Messages:
    1
    OK, Long story here made as short as possible....

    New owner of a house built in 1949. This is a single story ranch on a slab with a decent attic.

    I am remodling the bathroom and found the galvy hot water lines (coming up through the slab) into the bathroom have been replaced with copper lines coming through the attic. I don't know how they were disconnected or which way the original galvy lines are routed. They are not capped in the bath wall so obviously somewhere else there was a problem at one time.

    So... as I remove water valves I discover that my cold water galvy lines are showing their age with rust build up and I decide, after much discussion, to run a new cold supply line (PEX) from the laundry room to the bathroom via the attic. In the laundry room there is a 3/4" supply line coming in and the washing maching, outside spicket and hot water tank run off of it. I figured I would "t" into this line to run my bathroom cold water line.

    My problem is that today I discovered that my 3/4" supply line in the laundry room is actually 1/2" line which adapts into 3/4" about 2 inches from the slab, then back to 1/2 into the water heater.

    So, other than spending thousands on a plumber I have 2 choices; I can stick with my plan and run the cold water line through my attic and into my bathroom (sink, toilet and bath/shower) after I tee from my laundry room OR I can just replumb the bathroom with fresh line and use the existing galvy that comes up from the slab.

    Which should I do? Thanks in advance for any info.

    I do wonder if my bath hot supply pipe originated from the laundry room??? I don't know these things.

    Is splitting one 1/2" line into one cold and one hot 1/2" line going to reduce my volume too much?

    edited to add: Home is on city water supply.
    Last edited: Jun 29, 2009
  2. seaofnames

    seaofnames DIY Senior Member

    Messages:
    162
    Location:
    Mission, BC
    How hard would it be to get rid of the galvy pipes in the slab and re pipe accordingly? Its not gonna get any better. Have at least a 3/4" supply from the city would be best.

    The volume thing isnt a huge concern, you will notice it if your washing machine is filling up and you are having a shower or flush the toilet, but its not that bad to split 2 or sometimes 3 fixtures on 1/2"(for DIY, anyway)
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    Pex

    Now, what good would it do to leave the underground galvanized lines connected and run a "bypass" overhead? If you run a new PEX line, DISCONNECT the underfloor one so it does not leak someday even though you are not depending on it.
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