Tracing PVC Pipe in Concrete Wall of House

I do not now what your budget is like but various company's like Stanley, Zicron, Martindale Etc. make very inexpensive Stud/Metal detectors. These will be available at your local hardware store and will help you trace the fish-tape in the pipe without a problem.

I don't have a lot of hope this will work, but I happen to have a stud finder, so (if it were me) I'd give that a try--it might work if the 2" pipe is not too far from the surface of the concrete, and might read sort of reverse--the solid concrete with no pipe might show up as studs, while the slightly hollow area where the pipe is might show up as no stud.

If you have or can easily borrow a stud finder, it might be worth a try.

Otherwise, yes, the magnet and compass is worth a try.

Hmm, one other idea, only if you can borrow or cheaply rent the equipment (or rig something up) might be a cable thumper--ahha, this brings two ideas:

• first, the cable thumper is a device used to detect faults in de-energized cables--it periodically provides a current to a cable to make an arc at the fault, and then a detection device is run along the cable to find the fault. I'd take a small cable to use like the fish tape and put an intentional short on the end of the cable (you might have to read up on how the thumper works, maybe instead of a dead short you need something that is just a place with (intentionally) damaged insulation (at the head of that cable)--snake it into the wall and follow the progress with the detector, or
• rig up something on the head of the fish tape that makes a(n acoustic) noise, then try to trace it with a (mechanic's) stethoscope...not sure what to use to make the noise, but there must be something, either electrically powered, or even just some kind of windup thing...2" diameter might allow you to insert the mechanical (or electrical) works from a music box, or maybe just an electric buzzer of some sort (piezoelectric or something more traditional)

Good luck!

In the scheme of things, a metal detector might be the way to go, they can be relatively inexpensive, or you could borrow one, although you may need to run copper wire down the pipe rather than steel tape so the readings will be different than any rebar that is in the wall.

Another thing that may be worth a try is to use a plumbers "snake" instead of a steel tape. They are designed to navigate around corners.

You don't give dates or other details but here is a comment anyway. If the roof was redone since the initial construction (or even the initial construction too) the roofer would possibly cover any small pipe that was not covered by explicit instructions in a roofing contract. I had expensive coax cable and other radio antenna items covered and/or destroyed by a roofing firm once. Some of them (not intending to offend good contractors) are going to get the job done as fast as possible and not waste a single second on anything that gets in their way.

I worked on a pipe once by taping a cheap USB camera (self illuminating) to a plumber's snake and running it up the pipe with a laptop computer connected to the other end. Not a real great system, but for the $29 investment I was pretty happy with the results.

If you are looking for the termination (other end) of the pipe, hook an air compressor up to it and pressurize it. You'll hear the air escaping from the other end.

If you want to trace the route of the pipe, good luck.

GA to Lynn,

The air method would seem to be the cheapest and less destructive way to begin.

Hilti tools has a hand held device that can look into concrete wall to locate conduit and re-bar.

I all ways look for reasons to get more tools.

You need an oscillator attached to your snake, You just follow the tone it emits with a coil attached to an amplifier

http://www.google.co.uk/search?q=oscillator+for+locating+pipes&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=mm4HTc_7N8qKhQegwKzvBw

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http://www.cscope.co.uk/

you attach an oscillator like this to the end of your snake

http://www.cslocators.com/products/index.php?id=7

and get somones metal detector and listen for the tone.

you cdould use any tone generator from a kids toy etc taped to the end of the fish

Please don't take offense Peter, but I nearly ruined my keyboard with coffee when I read the first line of your post.

Relax, the unit comes with a range of adapters.

It's not like one size has to fit all snakes.

My first thought was to blow smoke into the conduit and see where it comes out. I have no specific knowledge of smoke generators (they are used to locate sewer leaks and illegal connections) or how smoke might be forced down the conduit, but perhaps CR-4ers could. Good luck.

smoke bomb for fumigation purposes would do

Blow smoke up your pipe? Sounds like it's worth a try.

Good morning JOHN H VAN ALLEN.

You have gotten a few good suggestions already (I like the smoke idea). I would expand on one of them. An observation: an exterior wire pipe should have some sort of weatherhead on it, maybe just a downturned gooseneck fitting. Water vent pipes would be open to the sky.

I presume you wish to pull wire through the pipe after discovery. Using the air compressor as a source, feed a pull tape into the pipe at your known location. The air will carry the pull tape to the roof termination, and you can go from there. The tape must be fairly substantial, but still be sort of 'fluffy'... there are a number of commercially available products available for this specific purpose. A usual practice would have been for the contractor to have left a pull tape in place, but it may have been removed.

If you are using a sparkies draw tape, it will jam on its own because of the size of the tube! You need a more rigid tape first like the type we use to send along large tubes in the road! (It's about 8mm diameter or bigger!) Get someone on the roof, and send the heavy duty snake up the tube! When you hit the stop, get the guy on the roof to locate the taps and there you go! (unless of course, it's blocked further down!)

Wow, I certainly appreciate all these ideas. Some may not work due to the poor workmanship in this country where I live. Example, sometimes contractors bend the PVC simply by heating it with a piece of burning paper so curves get collapsed or kinked. Some are outright damaged so holes will exist. Sometimes I find water as well which can ruin electronics. The fish tape I am using is quite strong and stiff enough for bigger pipe yet still bendy enough for curves. I will keep trying and thanks again. I guess by the response I'm not the first to have this sort of trouble. Yes I need to pull wires.

Regards

John

I have been intrigued by the Bose system. I would try a small radio with the speaker, playing something with a pronounced base, against or close to the end of the pipe. Follow the sound if you can, but if you can't, search the house for it, it should come mainly from the open end. The Bose produces an amazingly big thumping base sound from a small source by running it through a pipe.

Another way is to push some 20mm pvc hose pipe up the tube until it reaches the other end or the blockage, then blow into it like a trumpet. Easy to hear!

You may want to try inserting a pipe tracing wire up the PVC pipe and use a rented or borrowed pipe tracer, the type used by municipal water departments. I've used them before when I was a City Engineer, some years ago, and more recently I used one to trace out where my septic system pipes (PVC) were located before constructing my tool shed foundation. Most of the newer ones can detect the metal tracer wire radio frequency down to 12-15 feet below the ground surface, so there shouldn't be a problem tracing the pipe path buried in concrete. Contact your local water department and see if the can lend you a hand by using the aforementioned equipment....or rent it from a construction rental company near you. That's what I would do.

I have my doubts about using a metal detector to detect a metal tape or wire due to the presence of reinforcing steel buried in the concrete.

Also, doubtful pumping smoke into the PVC pipe will work as well, especially if the PVC pipe sections (and any bends and other fittings) were solvent welded (glued)together. That, and if the pipe is buried deep in the concrete mass there's no way for the smoke even under high pressure is going to leak through the concrete to the exposed surface. You should also keep in mind that the original plumber(s) who installed the pipe may have "capped" the top of the PVC pipe with a solid PVC cap or duct tape so as to prevent water, birds and insects from entering the pipe.

Good luck!

Signed,

CaptMoosie, PE/PHD

Civil, Structural & Environmental Engineer

I would generate a ticking sound and fix a series of capsule mikes (like those used in electric guitars) to the wall. Intensity of the sound captured by each mike will be of help.

This is not rocket science one guy almost had it, a normal 20 dollar stud finder can be set over where the pipe is known and turn up from there to go off on the non hollow wall as if the wall was a stud. Builders do it every day to find cavities to use.

The stud finder might work but it will be a lot more fun to try all the other suggestions first.

In a similar fashion to my first idea of the stud finder my 2nd suggestion will be to instead of using the fish-tape to use a electrical wire loop pushed in the pipe until it reach the end or stop. With the 2 ends of the loop sticking out the starting point connect mains voltage live to the 1 wire and in series some kind of load like a lamp to the other wire and neutral. take care that no voltage is connected during the hooking up procedure. when mains are connected there will be a current flow trough the loop and this can be detected and traced with a mains voltage detector brush or pen or similar detection device. again these you will find at your local hardware store very reasonably priced. I use these every day to detect the presence of high voltage in unknown vacuum tube amplifiers before i push my fingers in to do any work. it prevented me from getting a nasty electric shock more than once. good luck.

Problem is that most stud funders only work to around an inch and a half with concrete block. Not designed for concrete but for wood construction. Even worse if house was built using ICF forms.. as the insulation gives more space before the concrete.

I am hoping to find cheap solution myself as here where I am the electrician that set up the building died without leaving the electrical drawings where they could be found. And the masons did not mark the walls with spray paint. My USA stud finder has only found one rebar. In twenty-five feet of wall. My chisel has found eight more.. but no electrical conduits..

Normal practice here is to place the conduits in pockets away from the rebar... ad crimp the end of the pvc tube over so concrete can not fill it.

Of course the other normal practise is to leave that block cavity unfilled so tapping can find it.. and to mark the blocks with a backward p...

Neither was done here..like i on way fifteen of searching for the pipes by hand with no electricity for my sds drill

I like the "blow smoke up your pipe" idea...try the air pressure first to ensure that the pipe is actually OPEN on the other end. Someone may have put a cap on it to prevent things/bug/animals from going into it.

Since you are in a warm climate you could might circulate something cold in the pipe for a few minutes and get someone with a thermal imaging camera to scope the wall.

Concrete is a good conductor so the pipe should show up fairly quickly.

1. You are in the Dominican Republic. chances are the interior wall is non-load bearing and has very, very little rebar in it. It should not give you a problem. At least, such is the common case here in Panama...

2. Chances are, the concrete used (I would suspect block) is most likely very, very soft. If all else fails, you could most likely just chip out the concrete to find the path and then patch it later. In this part of the universe, concrete is often used as a temporary building material...This is common practice here in Panama.

3. The acoustics ideas are probably the best solution, but you do not need all sorts of fancy equipment. Use a "mechanic's stethoscope"- a screwdriver, the metal point in contact with the wall, the handle held against the ear. Have someone rattle the fish while you listen to the wall. Surprisingly effective...

An even easier method than compressed air might be to simply hook a vacuum cleaner hose to the pipe. If you do find a place where you think air is entering the pipe hold a lit cigar in the vicinity and trace the smoke. -Illya

Hi John

There are now a few people involved and a few days have gone by. I saw this thread a few days ago but thought that someone would come to the fastest and easiest, most reliable, efficient solution. This has not eventuated so here is what I would have done on day one.

1. Forget about the pre-existing pipe.

2. Put in a new conduit to your exact specifications.

3. After that is finished (end of day one) have a cold one and sit back.

4. Equipment required: angle grinder with appropriate disc, chisel, dust masc, masonry drill bit, elbow grease and some filler.

Why worry about a skeleton in a closet if you can start from scratch.

Happy chipping, Ky.

Thanks for yours and all the other great ideas. The idea of a new route is of course logical but a "human element" interferes. The house owners' wife is extremely fussy and when I suggested a new route at the beginning she was in complete opposition insisting that the tube went to the roof and that we find it. She doesn't want any messy work and associated noise, dust, workers, etc trampling around her beautiful house, hehehehe.

Some of the best plans are often stopped for the most astounding reasons.

Best Regards

John

I get it

As long as her lovely husband foots the bill all is good.

Hope all goes well, Ky.

Just come accross these people who sell the typr of equipment you may need

http://www.dartsystems.co.uk/shop/index.php?main_page=advanced_search_result&search_in_description=1&keyword=pipe+location

Can you get in to the attic space, most builders would not penetrate the roof with an open pipe that could cause interior damages from the weather.

You might use an electric cord tied on the end of your fish tape, when you get it to the end of your pipe, just plug it in and follow its path with a electronic stud finder with the electrical mode turned on.

On the low budget side you just might trace the pipe using a IR thermometer and blowing hot air in the pipe or use heat tape taped on to the fish tape to trace the pipe, I just don't know how thick the wall that the pipe is in.

These concrete houses in the tropics don't have attics like up north and the walls are 8 to 10" thick. Yesterday I introduced the steel fish tape with a tiny powerful magnet attached to the tip with heat shrink tubing. I also marked the fish tape with distances so we could estimate how far in it went. I then had my assistant introduce the tape and I searched for the magnetic tip with a sensitive compass. I was able to follow it vertically up the wall from the outside until reaching the ceiling platform at 20ft in then my assistant felt resistance which was a 90 degree curve. After the resistance he was able to introduce another 20ft but I couldn't follow because of the awkwardness of the roof and then he felt a second resistance which was another curve. 13ft more went in and we hit the blockade. At this point we needed to listen using wine glasses but got stopped due to logistics (We were not allowed into that part of the house) so we will return next week to continue. I am afraid we will have to break some cement sooner or later and this is a very nice residence so we are afraid what the owners may say. Oh well.

I really want to express my gratitude for all your ideas. I must say I was surprised I got so much interest in what I thought wouldn't be such an interesting project. Thanks to All and if you have anymore ideas go for it.

John

Thanks for the feedback! Let us know the final result.

Yeah, good luck.

Another tip: send the Queen bee on a holiday. Although she is not in the 2" pipe she is a bit of an obstacle.

Gotcha

I confess I've only been reading on this thread at intervals, and so, may have picked up an erroneous view, but it does seem to me that the odd thing about it is that a)The "QB" (not a football player) does seem determined that you will find and reuse (however she has in mind) the course of that 2" pipe, and b) She IS paying for all the hours spent (otherwise, what are you doing still working there?), so, c) It IS a paying job, and pretty much sounds like its fulltime. So, no matter how stupid it may seem for the QB to keep putting money into what either a) isn't worth doing, or b) won't pay off however it is she thinks it will, at least in terms of money sunk to value gained, she IS providing gainful employment.

I hate doing jobs that my conscience tells me I'm doing only to milk the value, and I won't let a job go on and on, IF I can get it done quicker, better, less expensively, without offending or otherwise alienating a customer. OTOH, wealth doesn't ONLY go to smart people, and sometimes, even wealthy people insist, for whatever personal reasons, on wasting money.

So, if I had as much time on this job as it appears you do, and wasn't getting where I felt I needed to be with it, I'd probably be weighing the balances on a)what does it do to my company's rep if I have to walk away from it, b) How badly do I want to avoid her hurting my company, c) How badly do I want the money that keeps flowing, and d) (If you have access to any information on this) How much longer can I accept/stomach/be a part of her driving herself and others into their own financial ruin.

And if, having weighed all that, I decided to stay on, I'd probably go search out a team of two, or three, reliable and very stolid, plodding, but skilled workers that I could hire on to do only that job. Then I'd monitor, advise, and pursue putting my company onto more "normal" jobs.

Probably apply all the pressure I could to get her to make one of two decisions, before I followed that last path, since it fits the third choice of decisions. Decision point one would be based on "If you really want us to find the path of, and reuse THAT pipe, you really need to consider letting us break walls". Two would be "OK, that won't work, so it's alternative is to realize that you are throwing bad money after good, and MY conscience tells me I at least owe it to you to emphasize that point. Point three would be to concede with good grace, and good humor, that she IS paying for the job, and go find that spare dedicated crew I mentioned earlier.

But if your company is like my son's (who is a contractor, and runs his own contracting company, in Mid-Pennsylvania) you can't afford to have all your own personal skill and time tied up in one place with someone who is obsessive about this little detail, because, if I'm guessing correctly, YOU, PERSONALLY, need to be out beating the bushes, drumming up the next paying project (hopefully more sensible than this one seems) to keep your company visible on the market, and viable on the job.

My two cents. And I don't do your kind of work, so maybe my frustration, were I in your shoes, would make me unsuccessful at your kind of work. Don't know. Don't do the same kind of work. Just observe, and offer my <skewed> viewpoint.

I don't know if you can still rotate (twist) the steel fish tape past the two curves, but you might give it a try. If you are able to then it should make a lot of noise through the full length of the pipe. That should give you something to look for with your wine glass.

That idea brings to mind trying a Plumber's snake (with the screw type basket on the end). As you twist that one into the pipe, it will worm its way around obstacles via the screw tip on the basket. One of the 50 foot ones just might reach far enough to do what you need to do, and in a 2" pipe, it will certainly rattle as it twists around the bends. I don't know if you can twist the fish tape, but I KNOW you can twist a plumber's snake. I had to root out an ice dam more than 40' into my pipes one winter, and the snake got past everything the ice had pushed up, bored through the slushy ice at the blockage, and broke it all loose. Hot water did the rest, but that's a different story.