seeking plumbing advice

Discussion in 'Shop Talk' started by John_in_Houston, Apr 18, 2005.

  1. John_in_Houston

    John_in_Houston Well-Known Member

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    Hey all,

    I need to expand the plumbing on the old post office building we own.

    Right now, we have a sink and toilet and I want to add a shower and washing machine drain.

    I've ripped out the drywall and have exposed the copper cold water line that feeds the sink and also have exposed the pipe that the sink drains into and also connects to the vent.

    The drain pipe is metal and goes into the slab. the sink drain line goes into the side.

    For drainage is it possible (or even a good idea) to cut out the metal drain pipe near the slab and use pvc to connect to the vent? That way I assume that I could use pvc couplings for the shower, washing machine, and replacement sink drains.

    Are there 'one way' couplings that would prevent a backed up sewer line from coming up the shower?

    As for the water intake, I was thinking of cutting the existing copper cold water line and putting on a compression coupler to 't' off lines to the shower, washer, sink, and a water heater. I've been thinking about getting an electric on-demand water heater.

    Any advice or warnings? Thanks!
     
  2. cfabe

    cfabe Well-Known Member

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    On the drains, you're going to have to go into the floor to run the shower drain unless you are planning to put it up on a pedestal. Is it cast iron? They do make a fitting that will let you splice in a piece of pvc and use pvc for the new construction. I'm not familiar with any one way fittings for drains, I think that'd be very likely to get clogged. If the drain line clogs, the water will back up into the shower, but at least the shower is easy to clean out.

    I'd use sweat soldered fittings instead of compression fittings, they're less likely to leak if you get them soldered well. An on-demand water heater can save some money, espicially if you're not going to be using the hot water often, but the catch is they require a ton of power to operate, like 50-100+ amps depending on size, which can be expensive to install and may tax your building's electric service if it's small.
     

  3. John_in_Houston

    John_in_Houston Well-Known Member

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    Hi cfabe, yes I was planning on putting the shower on a pedestal - I really don't want to mess with the concrete and since my wife and I aren't very tall, it shouldn't be that much of a problem.

    I'm pretty sure the existing drain is cast iron - I'm glad there are fittings for that.

    I didn't know the on-demand needed that much amperage - I might have to rethink that.
     
  4. mtman

    mtman Well-Known Member

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    i agree solder is better the fitting your looking is called a...no hub cast iron can be cut with a sawzall if you dont have a chain snapper keep in mind showers are allways 2 inch drain and so is washing machine
     
  5. mtman

    mtman Well-Known Member

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    btw if you use a tee make shure its a waste tee not a regular tee
     
  6. John_in_Houston

    John_in_Houston Well-Known Member

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    What height should I plan on using for the pedestal shower?
     
  7. mtman

    mtman Well-Known Member

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    that youll have to measure i forget the height of a 2inch. trap youll have the nipple comming out of the shower pan and the trap
     
  8. John_in_Houston

    John_in_Houston Well-Known Member

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    Thanks, this is great advice - never done this before.

    Do I put sand under the shower for support? I think I read something like that somewhere before...
     
  9. mtman

    mtman Well-Known Member

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    well thinking you allready know you have to put a ellbow on there to so make shure you measure with that allso
     
  10. agmantoo

    agmantoo agmantoo Supporter

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    Take a bag of brixment and make a BIG doughnut out of the mortar and while the mortar is wet set the shower. The mortar will squish out forming a base to fit for the shower. Leave the shower alone ( do not step in it) until the brixment sets up and you should be fine. You can fabricate a "running trap" for the drain and it will minimize the height thus keeping the shower low to the floor.
     
  11. durangoranch

    durangoranch Active Member

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    John, If you are going to put it on a pedistal it wont need to be that high, but make sure you have the proper way to cut the drain pipe in the wall. If it is cast iron they make special cast iron blade for a sawzall(recipricating saw) you will need to set up your 2" p-trap on the floor and run a dry fit of the pipe over to the drain. that will tell you how high you will need to go. as far as the transition from C.I. to PVC get a Fernco coupling of the same size. It being a sink drain it will most likely be 1 1/2" youll need a 1 1/2 x 2 sanitary tee for the branch. then re conect the vent with another fernco, these will slide all the way over the pipes for ease. They use a 5/16 nut driver to tighten them.
    As far as the sand goes, good idea for support tof the p-trap. You can build the framing and deck it with plywood with a hole for the drain, tou will need nothing more than that. Home Depot sells 3'-4' shower bases that sit directly on the floor. I have been a plumber for 12 yrs so if you need any advise just pm me. I would solder the copper if you are able. If not you could go with compression. If you solder, make sure you clean the pipe with plumbers sand cloth and the fittings with a wire fitting brush and use plenty of flux on both joints. then apply heat and push the solder into the joints. Hollar if you need
    Spencer
     
  12. idahodave

    idahodave Well-Known Member

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    The on-demand elect water heater I had didn't work too good...It was a 9 kw heater, but the water temp coming out varied greatly with flow. We had a hard time using the shower without freezing/burning, normal water pressure fluctuation was enough to cause quite a change. If you want on-demand go gas.