Hi,

I need to separate my waste drainage from my neighbour but this means either digging up the concrete floor to find where the connection of his waste pipe to mine is or capping all my existing outlets and creating a floating floor through the house with new piping (the bathroom will be difficult since it is a wet room tiled floor and the drain again goes underground.
Which is the better of the two evils?
And is it safe to start making holes in the floor?
I still would have to dig through the concrete near the back door for the pipe to exit where the existing waste pipe does to make a new connection (1.2m below ground) to my septic tank.

Any ideas?

JD

Hey JD,

We need more details before we can answer. I don't under stand. Is there one septic tank servicing two plumbing systems? Why do you want to run a separate drainage system? Since this involves two systems eho pays the tab? Is this a duplex, condo, or what? Could you scan a diagram of the system for us? Regards, Tom

Yes there is one small septic tank with absorption system serving myself and the next door neighbour. The house is two houses together (one house but split). It was built last year but with the plumbing as one and the septic tank cannot cope with 4 adults and 2 children so we have agreed to try to split the waste pipes, it doesn't matter about who foots the tab. The reason being that we had a back up into our house and the neighbour had no idea and kept using the water, it made quite a mess.
All the waste piping is on the ground level (bathroom, sink etc) with the pipes running under the concrete floor. I don't have a diagram to scan since the builders didn't exactly draw anything, they simply installed it as cheap as possible and sold the house.
And so all the waste comes out of one pipe 1.2m below ground through the rear foundations. Under the floor somewhere my neighbours piping connects to the main outlet.
I have no problem digging up the concrete floor (I guesstimated where the pipe went, made one hole to have a look and found sand under there and the toilet waste pipe) and replacing it since the house is like a building site anyway, but only if it is safe to do so. The perimeter foundations should be holding up the house - not the floor?

You have no choice but to follow the main back to the junction point and separate the two systems and bring them out individually. You may take the floor up to do this since the foundation supports the building, not the floor.
You will then have to contract out another septic tank and drainage field. You found sand when you dug a hole? Do you live in Florida? Regards, Tom

Thanks, I appreciate it.
The sand I found is building sand and coarse sand, further below this is clay. But I live in Estonia - not the US, but I saw this forum was very good for help and I noticed your comments particularly, very helpful.
The neighbour will arrange his own septic tank once I have done the pipework which is fine by me, and I will keep the existing one.
But I guess I have some work ahead of me digging out this floor. I'm hoping the original builder has some idea of the location to make it a little easier so I don't have to dig it all.

Getting ahead of myself, but:
1. When I do find the junction point and bring out the second pipe, what about taking it out through the foundation, I'm guessing there is only room for the current pipe?
2. The existing concrete is about 80mm thick (with iron latticework set in it - not sure of the tech term) and sat on a plastic damp proof layer and then polystyrene or styrofoam blocks of 100mm. And then building sand.
I guess I have to replace the floor pretty much as is now but how to make the new concrete base is a worry.

" I live in Estonia - not the US, but I saw this forum was very good for help and I noticed your comments particularly, very helpful."

WOW! I'm doing "service calls" over in Russia/Estonia, ( You'll pardon me if I'm not politically correct here)
On behalf of the Site Administer, the Moderators, the experts and myself I wish to thank you for the nice compliment.
"The house is two houses together (one house but split)."
Over here we call that a"Duplex".

"1. When I do find the junction point and bring out the second pipe, what about taking it out through the foundation, i'm guessing there is only room for the current pipe?"
Bring it out as high as you can and notch the foundation. After the pipe's through the notch then fill the notch back up with cement.
"2. The existing concrete is about 80mm thick (with iron latticework set in it - not sure of the tech term) and sat on a plastic damp proof layer and then polystyrene or styrofoam blocks of 100mm. And then building sand.
I guess i have to replace the floor pretty much as is now but how to make the new concrete base is a worry."
I don't understand. Define "floor" as per against "concrete base"?
Is the concrete floor a sub floor with another floor laid on top of it? Is this a concrete slab house or does it have a basement. Regards from Sarasota, Florida, Tom

Sorry to confuse the issue, the floor is the concrete base. There is just one concrete slab which is my floor at the moment. Here is a couple of pics so you get the idea. http://jdmorrisn.blogspot.comThere is no basement. From the outside you can see where the mains water and also waste water enter/exit (in the trench). Inside you can see the concrete floor. Which as I described is concrete, 100mm styrofoam, plastic membrane and then beneath that is building sand.

In english terms my house would be called semi-detached. In estonia they just keep it simple and call it a house!

And I hope you don't mind when there are lots of questions, because I have very many?

JD

http://jdmorrisn.blogspot.com

Good morning JD

"And I hope you dont mind when there are lots of questions, because I have very many?"

Ask away. That's what we're here for. The advice we'll be giving you will conform to US Plumbing Codes. These codes are enforced to insure uniform plumbing and to protect the nations health. Next question? Regards, Tom

It seems my neighbour may decide to remake his own plumbing - which is good for me, saves my week for something else instead of digging up concrete.

I have a titan src tankless water heater, now in the US you have 1/2 inch copper pipes to use to connect to this, we in europe have 1/2 inch pipes also - yet for some reason does a US 1/2 inch not equate to a european 1/2 inch? Is it like a bakers dozen?

JD

"I have a titan src tankless water heater, now in the US you have 1/2 inch copper pipes to use to connect to this, we in europe have 1/2 inch pipes also - yet for some reason does a US 1/2 inch not equate to a european 1/2 inch? Is it like a bakers dozen?"
It depends on whether it's ID, (inside diameter) 1/2" or OD, (outside diameter)5/8". Cheers, Tom