Hello

I have been browsing this site and finding lots of useful tips - I am remodeling the 3rd floor of my 1920s house and converting a half bath there to a full bath. Because I have two young children, it might get to be a problem having one toilet not functioning during the remodel, so I thought a good first step would be to add a toilet to my basement prior to the third floor job.

All of my neighbors have basically the same house as me, and most have an old toilet in their basement that came with the house when it was built. Some have updated with a modern toilet at the same location... right next to the sewer stack that runs vertically through the top of the house.
My house has no toilet, but the cement floor looks as if maybe there had been one at some point. I have a feeling that I can just chip up the concrete and tie into the cast iron sewer line with the proper fittings and set a flange at the floor height for a toilet.. there is water supply right above for a number of kitchen fixtures and the hot water heater, etc..

My concern is the venting and discharge of water from the toilet - I plan to locate the toilet right next to the main stack that goes into the basement floor, following the guidelines for keeping the flange 12 inches from the wall or more. In my third floor I can see that the 3rd and 2nd floor plumbing/drainlines all connect into this main drain that I want to tap into in my basement, and that in the attic space, the top of this pipe is venting through the roofline. Will this vent suffice for the "new" toilet in the basement?
Is is basically a 4 inch cast iron pipe that runs from the basement floor up through the roof, so it does double duty as the sewer line and as a vent to let air in for the whole house plumbing. Is this the case, and do I need to add additional venting? I assume that when the toilet flushes air can enter via the roof vent and allow for proper exit of the waste water, but will I run into problems with other waste water from upstairs entering the new toilet, or will it just run past the point where I would tie in with a toilet flange?

HOPE THIS MAKES SENSE!

Thanks,

PE

This is a tough call. Section 1414.2 of the Standard Plumbing Code will allow you to install your water closet without a vent. However installing it directly next to a stack that will have the velocity of a three story drop of a bathroom discharge makes me a little nervous. Take a peek at your neighbors set up. How close to the stack is their toilet? Have they had any problems with backups? Let m e know what you find out. Regards, Tom

Thanks - I did look at one the other day... my next door neighbor's toilet is just a few feet from the stack... but I cant' remember if it is "uphill" from the vertical sewer line or downhill from where it enters the floor. Would it be a better idea to locate it prior to the place where the stack enters the floor ? What would help make it safer/better as far as installation goes?Is there any sort of special toilet or valve to help in these cases?

I hope this sketch works
| | pipe that goes up through roof and acts as sewer main
| |
-------| |----------------------| |----------------------------------- floor level
----------------------------------------------------------------------
|
Location of laundry |
In basement roughly where I want to put toilet

It's most likely your neighbors water closet's picked up from under the pour. I would come off the main under the floor with a wye instead of a combination wye and eighth bend to reduce the chance of any upper level discharge from entering the closet bend. Good luck, Tom

Thanks again... can you point me to any reference material on the wye vs. the combination wye and eighth bend that you told me about? Is there an online supply house that would have an image of this?

How does this effect the likelihood of material entering the joint?

Thanks!

PE

I have put up images of both a wye and a combo. I chose the wye because it will put the point of entry farther away from the base of the stack. Regards, tom

Thanks for going so far out of your way to help... I drew a quick sketch to sort of show what I can tell to be the situation - without really knowing what is going on under the floor. From the pieces you showed me, it looks more like you were thinking of tying in right to the vertical portion of the sewer line as it goes into the floor, not a few feet over? If you can tell from my rough sketch, I was thinking of putting the flange a bit over from the entry point of the sewer line, and tying in with some sort of coupling. I hope you can make out the drawing, I had to resize it down a bit, but you can zoom in!

Thanks again,

PE:)

No, What I preposed was to take up the slab and cut in a wye downstream from the base of the stack. The wye will run over to a closet bend that a toilet flange will attach to. You're not going to have enough room to install the toilet directly over the main as you've depicted. Regards, Tom