low spot in drain lines under slab

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seanbrise

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Well, looks like I have a major problem. We have had a slow draining toilet since we moved into the house. It wasn't noticeable as much first because the toilet was a low flow toilet, and they are slow anyways. So it got a little slower and I just got fed up with it. So, I flushed the vent lines with no help, I figured that a kid must have shoved something in the toilet so I replaced the toilet. The toilet I got was a big flusher, one of the toilets that can flush anything. Well, it got worse. So now we have a ton of water move into the bowl really fast, then it slowly drains again.

I called the plumber out thinking maybe there was something stuck in the pipes (was crossing fingers that it wasn't a level problem). He dropped a camera in and we found the pipes were full of water and stays full for at least 5-10 feet, then it went dry again about 4-5 feet from the edge of the house. So, I either have a low spot in that wet run, or the pipe exiting the house is a high spot. Weird how the plumber that was out said it was only a low spot. oh well.

So, he said they would need to rip up the bathroom, and maybe the babies room to relevel the pipes correctly.

My thought was what about lowering the pipe as it exists the house? If we drop it down a few inches, or up to 6" in the last 5 or so feet exiting the house then that should do it. The problem I am worried about is I would have to break out a chunk of the footer. Would this cause a problem? The pipe is sitting right on the footer, so I would need to break out a 6" section directly beneath the pipe, and cut out the rebar if they installed it.


I am very very handy. I built my last house (not this one), farmed out about 70% of it myself, and I did the rest. Minor plumbing experience, few sprinkler systems, some wood working, i have remodeled an entire kitchen, from sub floor, to electric, to cabinet install. So I am not afraid of digging into either one of the projects, I would really just rather not destroy the interior of the house.

Thoughts? Recomendations?

Sean
 

Redwood

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The digging needs to be done on the 5-10' that is backpitched. More digging needs to be done as needed to correct the pitch. Digging somewhere else will not correct the problem.
 

seanbrise

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How do i know for sure the 5' that has water is a low spot versus the area past that is not just too high? I didn't get this house new so I have no idea if the installer did it correctly from the get go.
 

Redwood

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You do know that the pitch after the 5-10 feet does not hold water...

Do you want to dig the 5-10 feet and correct it, or dig part of the 5-10' and then from there to the street?

I'll take the 5-10'!
 

Krow

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How do i know for sure the 5' that has water is a low spot versus the area past that is not just too high? I didn't get this house new so I have no idea if the installer did it correctly from the get go.
99% of the time, pipes with settle towards the centre of gravity. They rarely settle in an upward direction (unless you are in a sunami). I'm betting that your plumber is correct.

(assuming you are on city sewers) Lowering the drain outside the house would probably mean digging right to the city sewer, and if it is deep enough to allow you to drop to that level. The cost would probably exceed 3 times what your plumber is quoting you to fix the 5-10 ft mark
 

Master Plumber Mark

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you go troubles

I have seen that done before, tunnelling under a slab

if the drain leaves the side of the house fairly shallow

if the drain from the low spot to the outsid of the house is not a long span to have to lower

if it then turns downwards outside so you can actually lower the pipe outside in the yard to gain fall....

and if you like to dig like a ground hog

you might have a half a chance...


but I would not bet on it......
 
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Jimbo

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Let me ask you to clear up the description> Is the water standing in the pipe AFTER it leaves the house, or in the section BEFORE it leaves the house.

Basically, the slope has to be OK up to the point where you first find water in the pipe. And the slope is ok beyond the point where the water no longer stands. In between, there is a LOW spot.
 

seanbrise

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Water is being held in the pipe under the slab, not outside the house. Here is a real rough picture of the situation. From the exit of the house to where the water ended in the pipe is about 5 foot. You can see where the water is being held in the pic. sorry for the stick figures, lol.

plumbing.jpg
 
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Jadnashua

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If the pipe really has that significant slope outside of the foundation, you might be able to tweak things from outside. Going underneath the house can be dangerous, and it is tough filling things back in without leaving voids, too.
 

seanbrise

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OK, I went ahead and tore up a rather large section of the bedroom and have exposed about a 5' section of pipe. There is a really bad back slop on it so thats the problem no doubt now. So now is the fun part. How far do i go about digging under the house exposing the pipe to try and relevel it? And how do i lift it to readjust the slope without busting the pipe? Just looking for suggestions on it.
 

Krow

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How far do i go about digging under the house exposing the pipe to try and relevel it? And how do i lift it to readjust the slope without busting the pipe? .
This all depends on what the pipe material is and you will probably need to dig 2-3 ft beyond your initial 5-10 wet spot, then check the elevations of the pipe at its farthest points. The point closest to the front of the house should be lower then the point furthest from the front of the house.

You probably won't be able to lift the pipe without doing severe damage to the pipe. I would recommend replacing the section of pipe with new, especially if its clay pipe or terra cotta
 

Master Plumber Mark

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you are in it deep now....

I would not wish what you are doing on a dog..

....


if you tore up the bedroom and found the low spot,

I guess if it were me I would try to see how it leaves the
home.....


If you have already gone to all this trouble, you might as
well cut the line out completely out way before the low spot and then dig it out deeper and poke out through the outside wall and then re-connect out in the yard....

If you are lucky (LOL)

maybe perhaps you have a cleanout and standpipe on the outside of your home that you could simply re-connect to.....and plug off the line that you cut off inside..

just be sure to give it lots of fall this time.....


 

hj

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pipe

You have to dig from "point A", where the pipe starts to rise, until you reach a spot, 'POINT B", where the pipe is lower than that "point A" by the amount of pitch required to get to "pont B".
 

seanbrise

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the problem i have now is the pipe is actually following under a wall, so i could only escavate so far. I can tunnel i guess, yay on that one.

The pipe is PVC as the house is only ~5 years old.

So now i have to decide wether i go further into the house underground to raise the pipe up or just drop a new line from the low spot to the outside. I just wonder if i need a certefied plumber to do that work since it connects to the city sewer or if i can do it myself too. :) i ain't skeered!! would it be ok to have a step down in the pipe instead of just a slope? or maybe like a 30* angle down pipe to drop it beneath the footer? Or would it be ok to cut through the footer?
 
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Redwood

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would it be ok to have a step down in the pipe instead of just a slope? or maybe like a 30* angle down pipe to drop it beneath the footer?

This would depend on the elevations of the rest of the pipe. 1/4" per foot pitch minimum must be maintained.
 

hj

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pipe

Right now you DO NOT even know if there is a spot outside that is low enough to connect back to, or if you have to go all the way to the main sewer connection, assuming that is even low enough. You have to do considerable research before you even start, or everything you do will be wasted effort.
 

Southern Man

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the problem i have now is the pipe is actually following under a wall, so i could only escavate so far. I can tunnel i guess, yay on that one.

The pipe is PVC as the house is only ~5 years old.

So now i have to decide wether i go further into the house underground to raise the pipe up or just drop a new line from the low spot to the outside. I just wonder if i need a certefied plumber to do that work since it connects to the city sewer or if i can do it myself too. :) i ain't skeered!! would it be ok to have a step down in the pipe instead of just a slope? or maybe like a 30* angle down pipe to drop it beneath the footer? Or would it be ok to cut through the footer?

I recommend going under the footer instead of through. Backfill with washed pea gravel and tamp it good with the mushroom end of a Collins axe.
 

seanbrise

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ok, so i am putting up some pics so you guys can see what i am saying on the front of the house. There is plenty of downslope but i would probobly have to dig the entire span to the main sewer.

also, don't you just love how far over that bubble is? i still don't get how this would happen on a 5 year old home. ARG!!

And i have a pic of how far this is all happening from the outside edge of the house.
 

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Jadnashua

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Without knowing the depth of the sewer connection a the street, and how the rest of the line is run, there's no way to know if you can use an elbow. Whatever you use, I think you want a long sweep version so there'd be a chance of snaking it should the need ever arise.
 

Southern Man

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.....

also, don't you just love how far over that bubble is? i still don't get how this would happen on a 5 year old home. ARG!!

....

The plumber screwed up, that's how. Either that or your house is on fill and the whole thing settled a foot. But if that is the case you'd have craacks all over the place.

In most states there is a warranty period well beyond the stated 1 year. In NC it is 6 years, in SC it is 13. Call a real estate attorney.
 
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