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Eva 12-27-2008 05:27 AM

Finding waste pipes under a slab
I have a plumbing project where I need to locate the path of the waste line under concrete in a basement. The path doesn't seem to follow a logical course to the clean-out and I'm trying to avoid breaking up and entire concrete tiled floor. Use of a metal detector seems to have yielded no result as I assume either wire in the floor or scrap meal are making erroneous readings. In this situation might anyone have a viable solution to determine a close approximation of where and how this pipe may have been run. Basically I have two rest rooms that are old construction and not vented with the need to enlarge one bath and add a tub. I need to run the waste for the tub and add a vent stack. The area where the wall is to be removed to expand one rest room should have the waste line under it unless it took and extremely weird route. The area is large so again I rather not break the entire floor. Is there any readily available device one might rent with perhaps a probe down the waste line that sends signal or such to locate the position or some other method to efficiently ascertain location????

thanks Eva

DangerMouse 12-27-2008 05:44 AM

call or visit your local township office, they should have original plans for the home, permits issued, septic pipe's locations, etc.

"Is there any readily available device one might rent with perhaps a probe down the waste line that
sends signal or such to locate the position?" yes, there is. call around to tool rental stores, plumbing supply, etc.


DUDE! 12-27-2008 08:53 AM

When using a snake in the past to clean the pipes in concrete, I can hear the cable moving through the pipe and get a really good idea how its layed out.

Eva 12-28-2008 05:43 AM

plumbing ellusive pipe
Thanks for the suggestion , however the building was built in 1847 and the town in question didn't keep records back at the turn of the century when the plumbing was installed ie: why vents were never run since no code for such existed then and why I need add them now. Not until the 1960's was any permit ever pulled for any work and there is little if any documentation even from that time. It was a grange hall and 99% of any original work and renovations were done without permits or any records what so ever. The current inspectors sort of scratch their head and are tickled that the updates are being made but sadly no one on the town level has been much help. The contractors names are often written inside walls and such we have opened, but these people named thus far are long dead. The iron exposed is non conventional, far heavier then the typical type I have always seen, some commercial grade from way back and is in amazing good shape where exposed. I am rather awe struck the system works so well without a single vent, but it does incredibly well. The hub wall thickness by the lead is almost an inch thick at the face where usually what I see is like 1/2 inch. Place is full of strange stuff. Several pieces were also used for lolly columns and I have never seen stuff like this it has to be like schedule 160. Since it was a public assembly building someone way back must have wrangled a donation from some industrial company for materials.


Eva 12-28-2008 05:53 AM

the ellusive pipe
Thanks for the suggestion about the snake I'll give it a go. Thus far no local tool rental place has any devise for locating pipes but I am told the local gas utility does. I think I need to make a new friend at that company if the snake procedure fails to reveal the answer. I "think" they might have run a partition over the path of where this thing runs after more examination last evening. We found another clean out in a very strange place inside a wall via an access panel 30 feet away. I am really hoping that isn't the case. The clean out plug (threaded) is pretty fused and I'm a tad hesitant to go beating on it for fear of opening another can of worms and the location doesn't lend to getting a wrench on the plug. Old buildings can often drive one nuts, I'm almost ready to hold a sťance to see if the long dead plumber will be inspired to knock on the floor where this thing is. Oy!

thanks Eva

tribe_fan 12-28-2008 08:44 AM

If the Snake method soesn't work...

I may be off base - but I think that some plumbers may have equipement that they can send something in the pipe that emits a signal, then they use a detector to find it.

DangerMouse 12-28-2008 08:57 AM


Originally Posted by Eva (Post 203339)
I'm almost ready to hold a sťance to see if the long dead plumber will be inspired to knock on the floor where this thing is.

if those old pipes start knocking, you'll probably have a heart attack! lol


biggles 12-28-2008 10:39 AM

drain your hot water heater into the nearest point of the house drain and sweep the concrete with a laser thermometer and can of spray the floor before you start draining to get the overall temp....any rise seen will be the pipe out

micromind 12-28-2008 11:46 AM

I've located many underground electrical conduits using an underground locator.

This device has two parts, a transmitter and a receiver. The receiver looks alot like a metal detector, and is swept over the ground until a signal is received.

There are actually 2 types of transmitters. One connects to a wire contained inside the conduit, and the other is a small bullet-shaped device that is fastened to the end of a fishtape, and shoved down the pipe.

Once the pipe is located, and the approximate center is determined, the receiver can be angled at about a 45 and moved outward until the signal is strongest. This will give an approximate depth of the pipe.

Most electric utilities have these, and alot of larger electrical contractors as well. A well-equipped rental place will have them also.


MACPLUMB 12-28-2008 12:18 PM

Traceing Sewer Pipe

Eva 12-29-2008 01:26 AM

the ellusive pipe
The rental places are closed of course for the holiday weekend so Monday morning I'll renew the search once again. Most the local rental facilities are rather poor equipped as I myself seem to own more tools then they have. I'll broaden the call range to a larger radius.
On a pleasant note I needed to cut through a slate very steep pitch roof for the vent stack and set the roof flange and that went quite easily. I used a hole saw intended for ceramic tile to cut for a diverter which was a 5 inch hole saw, they had from 4 to 6 inch available for like 30.00 apx. Gentle pressure and the saw went right through the slate with a perfect cut without chipping or cracking the slate at all. I then used a 4 inch conventional hole saw for the wood roof sheathing holding the drill on a level horiizon to the roof itself and sawed through the sheathing also quite easily. . Set the flange with some roof calk and used a small masonry drill for a couple of screws to secure it and it went just dandy. There were several plumbers before they called to run the stack and no one wanted to get into the slate. Perhaps most thought to use a different type saw or sawzall or something and had bad experiences with slate So i figured I'd mention it in case anyone else ran into a similar situation. Those ceramic saws are basically carborundum fused to the cutting edge and a pilot bit to center them. Very simple to do this, the biggest pain was getting on the roof which a good ladder a repelling harness and some high tensile rope for safety was all easy as pie.

Once I find the darn waste line and tie in I'm home free. I do thank everyone for all the suggestions and I'll try some and let you all know what the solution ends up being. Having moved to a more rural area is a tad of an eye opener in finding specialty tools, I'm use to the NYC giant phone book where one can find almost anything.

Happy holidays Eva

JDC 12-29-2008 05:00 AM

Most plumbing companies have locating equipment. In fact, there are companies out there that that is all they do. (Underground Detective is one here in Cincinnati). Sounds like you're on the right track though. Good luck!

Eva 12-31-2008 03:10 AM

the ellusive pipe
Well nobody around here will rent or lend one of the detectors apparently because of the value of them. I went to the gas company and they said they no longer use them, they bury a wire spiral around pipes now that they send a signal on yada yada and that was a stone wall. I tried the DPW and was told they can';t lend out or use equipment for non dpw use. Called every pluming place in the phone book and no luck.

So here's the plan now. I have found someone with a laser themograph thingie and were going to put a inflatable ball stop in the cleanout area just before the street and fill the pipe with water. Then put a submersable heat coil in the toilet flange side after filling the pipe with water and try the suggestion someone made to detect a heat rise in the floor. Wish me luck. it's the little silly things like this that always turn into the real pains in the tail.

At least aspirin is cheap and readily available locally.

Thanks again everyone for input.


JRoot 12-31-2008 03:25 PM

Im in a similar boat in my basement, let us know how it works out!

Eva 01-01-2009 07:46 AM

ellusive pipes
Will do JROOT

I have someone this week helping me with the thermoscope routine so we'll see what happens fingers are crossed. Happy new years everyone.


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