[Nealtw]

That's a good question that I will leave to my wife to figure out (-; personally, I'd rather not have to break up more of the floor, but since it seems some of the "harder" things are already setup, maybe we can go that direction.

The fitting under the floor is it bigger more the size of the main sewer line or the same size as the pipe going down there.

Gently tap the floor with a hammer and see if you can find a thin spot, it still might be somewhere just under the surface.

 

[Matt1963]

I'm not sure where that goes. Do I dig out around on either side to see where?

You took that picture from the mystery hole correct?

 

[saxman00]

You took that picture from the mystery hole correct?

yes I did. I'll try the hammer trick that Nealtw suggested. From what I saw without moving more gravel, it looked to be about the same size pipe. But I could be mistaken.

 

[Matt1963]

yes I did. I'll try the hammer trick that Nealtw suggested. From what I saw without moving more gravel, it looked to be about the same size pipe. But I could be mistaken.

Well if you don't see a pipe going into the mystery hole than I have no idea why the mystery hole is there.

 

[icerabbit]

Same. It ought to be there for a reason. Some more digging and poking around is in order.

And, again the lines that go vertical then horizontal part way up the wall, group together are the vent stack lines, ensuring proper drainage and flow of the waste lines, by letting air in from the roof area. They possibly tie in somewhere with the bigger main stack.

Maybe through the realtor, or directly, reach out to the previous owner, to ask about the purpose of the hole, how, what, why, ... what the intention was?

 

[saxman00]

Same. It ought to be there for a reason. Some more digging and poking around is in order.

And, again the lines that go vertical then horizontal part way up the wall, group together are the vent stack lines, ensuring proper drainage and flow of the waste lines, by letting air in from the roof area. They possibly tie in somewhere with the bigger main stack.

Maybe through the realtor, or directly, reach out to the previous owner, to ask about the purpose of the hole, how, what, why, ... what the intention was?

I think we're at least the 4th homeowners of this house so that may be tricky. Every question we asked about the house to the immediately preceding homeowners was met with "I'm not sure" or "I don't know" so they were not very helpful. I'll see what I can find around the pipe that is there now. I'll also ask around with some neighbors as many of the houses in my neighborhood have a similar design.

Do you think there is a possibility I could tie into that pipe that is beneath the slab? Sounds like there probably will be some concrete work unless I can't find a pipe sticking up in that hole.

Thanks!

 

[Matt1963]

After seeing all your pictures it appears that the original layout was like this. Red line represents your wet wall at the head of a bathtub (vent in wall) with the blue lines showing tub directions.

Not finding a tie in or a pea trap somewhat squashes the guess.

Can't tell you if you can tie in without being there.

All indications point to it as a drain area.

 

[Nealtw]

I think we're at least the 4th homeowners of this house so that may be tricky. Every question we asked about the house to the immediately preceding homeowners was met with "I'm not sure" or "I don't know" so they were not very helpful. I'll see what I can find around the pipe that is there now. I'll also ask around with some neighbors as many of the houses in my neighborhood have a similar design.

Do you think there is a possibility I could tie into that pipe that is beneath the slab? Sounds like there probably will be some concrete work unless I can't find a pipe sticking up in that hole.

Thanks!

There is usually a floor plan for the basement lay out when they do this plumbing, the city may have a copy of that plan on file.
Can you do a sketch of the basement and show the pipes in the floor and that hole, maybe we will see a likely place the tub shower should be.

 

[TheEplumber]

@saxman00, You have almost everything you need for a lav, toilet and tub/shower rough in. You are lacking a trap. and water piping. The vents appear to tie to the main floor plumbing and the water is in the ceiling (the2 capped drops)
A shower needs a 2" trap arm, tub needs 1-1/2". You need to dig in the holle and expose the tee more to determine which of the 2 you can use

 

[saxman00]

Thanks everyone! It looks like I have some digging and research to do. When I start the project, I'm sure I'll be back. I have a lot more answers than I started with which is great. Thanks!

 

[StrongEagle]

It's for a bathtub. A hole deep enough to plumb the bathtub drain, with a p trap. There must be some place to connect to the drain line, or, they expectation is that you will cut and fit the bathtub drain to it.