# under-slab plumbing / DIY



## ruger9

OK. I'm a remodeling contractor, and I have installed a couple of sump pumps for friends, but I do not do plumbing (except in my own house)... I hire qualified plumbers for that. Problem is, I can't seem to find one who wants to work. I'm remodeling my 1st floor 1/2 bath (on concrete slab), and am going to expand & add a shower. All I want is a plumber to bust thru the slab & add a shower drain. That's it. Unfortunately, I can't get anybody to even call me back, even with a "I'll price the job real high because I don't want to do it" price. Unbelievable. Anyway, looks like I'm going to have to do this myself. SO...

How difficult is it to tap a mainline under the slab? Special concerns? I don't want to break thru the slab, bust a pipe, and not be able to fix it... that would render ALL the plumbing in my house unusable, because this is the "exit" of all the plumbing in my house... the main stack.

Can anybody point me in the right direction/give me some tips here?


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## Same Old

I've never met a plumber that wants to bust up a slab. They don't even like to drill through wood all that much. If it isn't putting pipes together, they're not too interested. 
My suggestion would be to bust up the slab yourself and get a plumber out to hook up the pipes.


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## ruger9

Same Old said:


> My suggestion would be to bust up the slab yourself and get a plumber out to hook up the pipes.


I actually have no problem with that- alot cheaper for me. My only concern was, what if I bust a pipe... I can't fix it, and the plumbing in my house will be out of commission until I can get a plumber there to fix it. How far in the substrate are the pipes generally buried? I've broken thru slabs before, but never over pipes. As long as I can be reasonably sure I'm not going to "hurt" anything, I'll bust up the slab myself.

Honestly tho- I'm genuinely amazed no one wants to do it for the "right" price.


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## Ron The Plumber

There is nothing that can't be fixed. Just take you time and expose things slowly. I'll come and do it for you, but at a price you can't afford.


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## ruger9

I'm a contractor as well. I know what it means to pay good money for good skills. Which is why I want to pay someone to do this- someone who has the skills. I just can't believe no one will do it. And affording it isn't the problem. The problem, apparently, is the "nice" work around here is so plentiful no one HAS to do the "crap" work. Nice work ethic.


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## mdshunk

Call one of the retail plumbers up who do mostly service calls. Tell them any darned thing to get them out there like "problem with the shower" (which would be true, because you need it hooked up). Once they're there, you own them for a bit to do the job. They can outline where they want you to make saw cuts in the slab while they go make the run for the fittings they'll need. :thumbsup:


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## Plumber

*how deep?*

Here In Indiana it depends on the builder of the house I've seen 4" of concrete and 12" of sand But I have also seen 6" of concrete and and 1" of peafill or sand. It's a trick question. I would personaly use an big sludgehammer 16-20 lb. If you can get your hand on one. It take a little longer this way. But you don't have to worry about the tip of the jackhammer going through an pipe.( A little tip get on your knees and swing easier on your back.) If you live here in Indy I would fix you right up!

Good luck!
Michael


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## POOLMANinCT

another little tip, just let that 20 pounder crash down on its own, you not going to smack the slab any harder if you "mad dog" it...

on knees to save the back?? mental note made
ray


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## dirt diggler

i can't really visualize what you're talking about

but if you're tryin to bust up concrete ...

the more you can cut (with a diamond blade) - and then go back with Dr. Sledge - the easier



but - ive only busted up concrete patios & decks

and I certainly do not go out of my way to gain that experience:whistling :laughing:


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## thom

Just my $.02

Forget the saw. To much exhaust/dust inside. Close the door, tape the bottom, open the window, put on your respirator/dust mask and go to work.

Use an electric jack hammer. 

Start at the location of the proposed shower drain and give yourself a 24" diameter hole centered around the proposed drain. Work a slot towards the commode about 2' wide. Stop about a foot away from the commode. 

Don't put the bit through the concrete. That's not the way to work a jack hammer. Take out small chunks and you will get there.

After removing the concrete, start digging. Find the 3" that drops below the commode. Best to go for the horizontal pipe but if it is the other way from the commode, the vertical will do.

Uncover enough pipe that the plumber has plenty of access. If you go for the vertical, open up the slab around the commode flange, about 24" diameter again. Since you will have located the pipe by this time, you should be able to avoid it.

Once everything is easily accessible and your trench is dug, call the plumber, explain what you need, what kind of pipe you have, and he should be able to do it in one easy trip.

If you need to run the water through the slab, continue your slot/trench to underneath the wall where the controls go and to underneath the wall where the existing sink/lav is and open up the sheetrock walls making the water lines easily accessible. Drill the holes in the sill plate for the plumber ahead of time and have all the prep done.

Make it easy on the plumber and he will make it easy $$ on you.


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## ruger9

Thanks for all the great tips guys.

I've used the electric breaker before, works great. I don't need neat lines, since this bathroom will be getting a subfloor anyway to install hardwood. And making a mess is not an issue. I gutted my ENTIRE ground floor for a complete remod. All I've got are studs & concrete.

My only real "issue" is, I don't know where the pipes ARE. I know where they enter the slab (within a 4ft radius I have the main stack, another drain from the upstairs bath, and a toilet), but am not sure what direction everything goes in. I'm assuming towards the main stack, which is in the wall between the garage & house. (There's also a sewer cleanout in my garage). I guess I'll just start at my proposed drain location, and work my way towards the toilet/main stack, and hopefully find the pipe with enough room to add it a y or t.

One of the plumbers (3 showed up, none will return my calls) mentioned instead of messing with the iron pipe, maybe, just maybe, I could tie in horizontally to the main stack (about 2 ft away), by putting a t on the bottom of it where it probably goes horizontal to meet up with the iron pipe.

Until I bust up the concrete, I won't know what I'm dealing with.

Thanks again for all the help. Any other tips welcome!


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## Ron The Plumber

The mainline under the slab will 90% of the time heads towards the city sewer street, most plumbers run out of the house in the most direct route towards it. With this in mind you might have a clue. If you want to know how deep the mainline can possible be, and it's close to where you plan on tieing onto it at, pull the closest toilet, look into the pipe, see how far it goes down before it gets to the 1st bend.


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## Same Old

You could call out a sewer cleaner and have him put his camera down there. You could map out your system pretty well in a few minutes with that.


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## smellslike$tome

ruger9 said:


> I'm a contractor as well. I know what it means to pay good money for good skills. Which is why I want to pay someone to do this- someone who has the skills. I just can't believe no one will do it. And affording it isn't the problem. The problem, apparently, is the "nice" work around here is so plentiful no one HAS to do the "crap" work. Nice work ethic.


It's all "nice work" if it's priced right. It's difficult to believe that you can't find a plumbing company that will even talk to you about it. What size is your market?


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## smellslike$tome

mdshunk said:


> Call one of the retail plumbers up who do mostly service calls. Tell them any darned thing to get them out there like "problem with the shower" (which would be true, because you need it hooked up). Once they're there, you own them for a bit to do the job. They can outline where they want you to make saw cuts in the slab while they go make the run for the fittings they'll need. :thumbsup:


I don't think this is very good advice. If someone calls me out and I discover that they just flat out lied to me I may just turn around and leave since I now have substantial reason to wonder whether or not I will ever be paid. Character counts. Even if I stay you can be certain that the price will be higher than it otherwise would have been because I do not trust you now. I still don't believe that he can't get a plumbing company to come out. As for "owning me for awhile", yes and no, you will pay a service charge to get me out there and look at what you need done. Once I get all the information I need I will give you a price to do the work. I will not however, stand around giving you step by step instructions on how to do it yourself. 

I have never been afraid of concrete. In fact I prefer to saw/break it myself so that I am certain it gets done exactly the way I need it to be done (try cutting/replacing cast iron pipe 2 feet or more below slab in the 1 foot wide ditch that that the ho cut out, it can be done but why do I want to). If I cut it I know it's right.


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## Grumpyplumber

* Diamond Saw*

*You can rent one for about $1-200 a day....set the depth to 6" and cut a small test square a foot from the stack...dig it out and reach in.*

*Mindful that you need PLENTY of ventilation...they arouse HUGE amounts of dust and they are gas powered (cough cough), but cut through concrete fast. (4 times faster than a rotary)*

*I have yet to buy one...I rent 'em for basement remodels...but for single fixtures I still use my rotary hammer...thats why I'm Grumpy. *
*(I gotta get my moneys worth outta the stupid thing)*


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## lazerguy

Out there at tool rentals, you can get some device that's called a ''sewer pipe locator''. Never used it myself, but I once saw a pipe trace that had been marked on a concrete floor using this gadget. Later they broke the slab and dug the pipe.

Another idea...I never tried this yet, but maybe would work just fine: Go to a Radio Shack and get yourself a $80 Metal Detector (like people use to find lost jewelry).
I think it would probably locate a main pipe under the slab, provided it is iron not ABS... ;o)
I use the gadget to clear up the grass/driveway of stray nails after a roofing job. Works really neat! You would never guess how MANY nails are lying there waiting to injure a kids' bare foot (or your 68 Mustang's tires) until you spot them out with the beeper. 

Once I built an electronic pipe-spotter. It had a small waterproof coil attached to a length of semi-rigid wire, and connected to a low-voltage AC transformer. I would insert it in the sewer pipe at the closest opening. It sent an EM field right through the pipe (no matter ABS or iron) and I could pick the signal with another coil tied to a sensitive digital voltmeter. Finding the place on the top of the slab where the signal was the strongest, marking it, then moving the sender coil a foot down the pipe, spotting and marking again.... I could trace out the pipe with decent precision.

Someone's gonna have to patent a portable X-RAY machine for us, someday... Cheers!


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## mahlere

I just have one question...what kind of GC/Remodeler doesn't have at least one plumber to help him out?


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## Ron The Plumber

mahlere said:


> I just have one question...what kind of GC/Remodeler doesn't have at least one plumber to help him out?


You will find a few on here, no doubt about that.


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## Ron The Plumber

mahlere said:


> I just have one question...what kind of GC/Remodeler doesn't have at least one plumber to help him out?


And you can bet, if I ever find a GC doing plumbing without a plumbers license here where I'm at, I will turn them in.


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## Grumpyplumber

*LOL, good call Mahlere.*
*Just a few months late*


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## mahlere

damn...i never even looked at the original dates...wonder if he's found a plumber yet?


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## dirt diggler

funny how

"The problem is nobody seems to want to work"

really means .... "nobody wants to work for me"

after awhile ... sooner or later ... these people seem to stand out more ... and more ... and more ...






Meanwhile --- you got 30 guys in the "ADDDDERRRRRRRRRRRRRRRR I WANANT WORK" section


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## POOLMANinCT

dirt you are clearly "addled"


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## The plumber

I love slab work. That's all I did for years, and I'll take a slab leak or remodel any day over fixing toilets. There has to be a good plumber up there that will jump on it. Maybe you should try the newspaper or lower forms of advertising for the guys just starting out that are desperate for work. They will cut you a super deal if they are hungry enough.


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## jayschaff

*Locate the pipes under the concrete*

Look up a Ground Penetrating Radar Service Provider. They will be able to scan the floor and tell you exactly where the pipe is as well as its depth. Search on google for a local contact. Gp-radar.com is a good start.


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## plumberman

Jay, I think after 2 years he has probly figured out or done his remodel by now.


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## jayson22

If you can't find a plumber to safely bust up the concrete, some concrete companies know how to cut the concrete not to damage the pipes. I was hired to fix a hydronic infloor heating leak and we had to cut up the entire basement slab in order to find the leak. I worked with a concrete company to do it and they didn't damage one line in the end. Don't know how they did it, even though the 1/2" heating lines where encased in concrete. I would cut the concrete myself going down no more then 2 1/2" to 3". Thats usually the depth of the concrete slap. I think cutting it is way safer then using the Jack Hammer.


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## jayson22

LOL, I just realized how old this post was..


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