Needing general advice

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by extremefire, Oct 30, 2007.

  1. extremefire

    extremefire New Member

    Oct 30, 2007
    The wife and I are building an intermediate home for while we are building our future home. Eventually, the new building will be used for her own business. We are going to be building on a 24'x30' slab and that is where I am needing some input. Both of our parents have built a pair of houses themselves, and I remodeled our existing home, so we all have experience working with plumbing, but not with plumbing and slabs. So I just need pointed in the right direction to where I could find more information on that.

    Mainly, is there a general distance you want the pipes out of the concrete for when the concrete is poured? What do you do do attach the toilet fitting? How do you go about hooking up the drain on a walk-in shower?

    Just the details for plumbing when building on a slab. We have the general plan for the plumbing down, just need the last details so we can grab the shovels and get the pipe in the ground.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    It isn't uncommon to leave a box around the areas where the tub and shower drains will go so you have some flexibility in installing the drain and having a chance it will align with the fixture you choose. You need accurate plans to determine a toilet install. If you use 4", you can pour the concrete right up to the pipe then cut it off and use an inside flange. If you choose to use 3", then you need to sleeve it so you have room to slide the flange onto the outside of the pipe. The toilet pipe needs to be blocked so it is vertical during and after the pour after finishing the concrete, or installing the flange will be a pain. Exact placement of the toilet pipe is important, too, as if it is off a little, you'll either have a large gap behind the toilet, or have to use a non-standard one, limiting your choices and maybe increasing the costs.
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  4. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Nov 8, 2005
    Hansville, Washington
    I've never done it, but I've poked around a lot of building sites and marveled at the process. Basically, they run a lot of strings over the site to define where walls will be, and install both supply and waste plumbing as if the slab and walls were already there. The objective is to allow pressure testing to be done before the slab is poured, for obvious reasons. Here, all under-slab supply piping is insulated to prevent heat gain/loss and contact with our "agressive" soil which eats up copper. Looks like they wind up within an 1/8" of where they want the pipes to exit the slab. Concrete finishers don't like all the stubs sticking out, I'm told.
  5. extremefire

    extremefire New Member

    Oct 30, 2007
    Thanks for the replies guys. Went out tonight just before the sun went down and got locations of everything finalized. Going to get a shopping list together and with any luck have everything laid in this weekend.

    Next I am going to have to look into PEX but that is another post.
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