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Thread: New bathroom in un-plumbed basement

  1. #1

    Question New bathroom in un-plumbed basement

    Hey everyone, been reading the forums for a while now, thought I should register and post my dilemma......

    I am about to start breaking concrete for our new bathroom in the basement, and have a few questions. Our house has two stacks, one in the north-east corner, and one on the west wall. The one on the west wall is the main stack, the north-east is for the kitchen. Where I want to install the bathroom is in the middle of the basement, right between the two stacks. When I start busting up the concrete, should I find a cast iron drain coming from the north-east stack draining into the west wall main stack? That is what I'm hoping to tie into for the drains in the new bathroom. Make any sense?

    The other question I have is for the venting. Is it possible to vent the bathroom downstairs out through the side of the house? Or, do I have to put the vent through the roof? I geuss what I am asking is if it is ok to have the basement bathroom vent lower than the other plumbing fixtures in the house? The new vent will only serve the new basement bathroom.

    Any ideas?

  2. #2
    Moderator & Master Plumber hj's Avatar
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    Default drain

    Even if you find a pipe, not necessarily cast iron, going to the sink it is going to be too small for your bathroom to connect to it. There is a lot more to laying out and installing a drain and vent system, than just putting a bunch of pipe and fittings together.

  3. #3
    Plumber Deb's Avatar
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    Cool Deb

    This is a really bad first project for a DIY person. Before you just start taking out concrete, I urge you to call a plumber for at least a layout. There is way more to this than you understand. The first thing I would be checking is that the main line is deep enough for you to get grade from the bathroom. The main will most likely need to be at least 12" deep (maybe deeper depending on how far away it is) to get the fittings in and the grade you need for a toilet.
    You need a 3" line for the toilet--unless the north-east stack is 3", which is doubtful, you cannot use this.
    You cannot vent out the side of the house. The vent must go up through the roof or join another vent above the flood rim level of the highest fixture. Every fixture must be vented. The rules are very specific.
    A bad bathroom is worse than none. I urge you to not go blindly into this. There is more to plumbing than sh*t runs downhill and payday is Friday;-)

    Deb
    The Pipewench

  4. #4

    Default

    I have been doing quite a bit of research on this topic, and have had a couple of plumbers in to have a look at the project. I have done several plumbing projects myself, including moving a kitchen sink to the other side of the room, replacing toilets, taps, copper piping, garburater and dishwasher install. Although none of these are of the scale of my new project, I feel somewhat comfortable in my abilities to complete this project successfully. I'm trying to get a better understanding of the plumbing world, hence my questions posted here.

    The stack from the North-east side of the house is a 3" stack, so I should have no problem using this line. From the way these homes are built, I have heard that this pipe is approximately 12 inches deep (4 inches of concrete, 4-6 inches of gravel, pipe will be in the mud..... ).

    Also, I realize that the drain piping will need to have a rise/run to it, and the way I've got everything layed out, that shouldn't be a problem (provided the main line is actually a foot down).

    I was afraid that the vent would have to go through the roof, that adds some extra work. I was planning on running a 1 1/2" ABS pipe up through a closet and exit out the roof to solve this. Has anyone had any experience using an 'Air Admittance Valve'? Here is a link to the website: http://www.diydoctor.org.uk/projects...nce_valves.htm

  5. #5
    DIY Senior Member Hube's Avatar
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    Default

    Try "Sani-Plus" for a system that you can easily install anywhere (toilet, basin shower/tub) without any thru the floor problems.

  6. #6

    Default

    At first I was going to go with an 'up-flush' system, however after some research, I heard mostly bad about these systems. If someone were to accidentally throw a condom or a tampon in the toilet, it could plug up an 'up-flush' system really easily, and make a really big mess of it. That is why I am avoiding using a system like this.

    Looking at my north-east stack, it appears that it is only a 2" stack. So, it looks like I'm going to have to tie into the main stack.

  7. #7
    Plumber Deb's Avatar
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    Default Deb

    You may want to post a picture or diagram of your layout and venting, including the fittings you are going to use and the distances you are running. There is a vast, vast difference between setting a toilet and installing a complete bathroom in a basement.
    Since you have to go to the west stack, I would be really concerned about making grade to the main--12" may well not be enough grade.
    I repeat, the first thing I would do would be to verify that the main has sufficient depth. How much depth does the closet flange and the closet bend need? How far is it to the main? What is your elevation drop for 1/4" per foot grade. Remember that you need to put in a vent within 6' of the top of the flange. And you need to be able to cut a wye or combination fitting into the main. Add all this up---are you going to make it?
    Check your depth first. And then get back to us with your venting iso and we'll go from there.
    Deb
    The Pipewench

  8. #8

    Default

    Attached is a pic of my proposed new bathroom. I would assume the only way to check the depth of the main stack is to hack apart the concrete around it? With a distance of 12', using 3" pipe, I would need a drop of only 3 inches, sound correct? What is the minimum vertical drop down from the toilet drain going to be? I've read up on our local codes, which only mentions a maximum vertical drop, which is 35 inches.



    (If you get a little red x, right click on it, select properties, copy and paste the link into your browser.....)

    The more I get into this project, the more complicated it is getting, but it also sounds like it is going to be a fun project. We're planning on using a Toto toilet, they are rumored to be one of the best?

    And thanks for all your replies! I really appreciate the help in understanding the principles!

  9. #9
    Retired Defense Industry Engineer jadnashua's Avatar
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    Default

    I don't think there is a minimum - you need enough to put in the elbow to get it to the horizontal; I think the preferred elbow is a long sweep, but don't quote me on that, I'm not a pro.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  10. #10
    Plumber Deb's Avatar
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    Default Deb

    Every fixture needs a vent. Your picture really doesn't show how anything is to be vented. I don't think that you will be able to run the toilet vent directly behind the toilet, and you still need vents for the tub, shower, and lav. With the grade considerations, venting could get interesting...
    Why don't you hire a plumber for an hour or so to lay this out for you and explain the system. You can certainly do the work. It is the little code quirks that get ya! Also, I generally find that novices use way more pipe and fittings than they need to. There are probably some shortcuts that would save both time and fittings $$$$.
    The concrete will need to be hacked away at some point anyway. Or if there is a cleanout, you may be able to measure the depth to a 90 from there. Consultation with a plumber would probably be well worth the time and money. You can learn an incredible amount in an hour. I would love to be able to consult all the time!
    Deb
    The Pipewench

  11. #11

    Default murf

    Before you start busting up your basement check out www.saniflo.com

  12. #12

    Default murf

    Saniflo has a great new product that will dispose of sanitary items and condoms. The Sani-best. www.saniflo.com

  13. #13
    In the Trades Gary Swart's Avatar
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    Default Basement bathroom

    I wouldn't shy away from the prospect of breaking out some concrete. It's a bit of work, but there are tools you can buy/rent that make it do-able. But I would strongly urge you to take the advice about getting professional assistance at least in the layout. Mistakes in this job would be very costly to repair. As Dirty Harry said, "A man's got to know his own weaknesses."

  14. #14

    Default

    Yes, by all means get an expert opinion.

    If you goof up, you'll have to tear open the floor again. Worse yet, the system will not work properly and that'll be a nightmare in and of itself.

    You could save around $500 doing the concrete excavations yourself. You will create a ton of rubble literally. You ight be able to "dump it" in your crawl space. Be careful around existing drains.

    A plumber with specified equipment or a roto-rooter type business can run a probe (transmitter) through the drain and with a special receiver "trace" the path the underground pipes take. Have him/her mark it with a permanent marker.

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