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Plumbing under slab?

Socsmm6

Well-known member
Joined
May 20, 2020
Member Number
724
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147
4” drain line under slab has a low spot where the guest bath is or possibly a high spot between the guest toilet and septic.
There is a clean out at both ends of 4” lines. We ran a camera all the way through from clean out to clean out. The problem area is within 8-12’ of the clean out farthest away from septic tank. Water pools up all the way to the outer wall at clean out.
Seems like I can feel a buckled spot in the slab through the carpet around where the low spot should be. Guessing im ripping out carpet and cutting out a section of concrete in my back bedroom?
I guess I could run a line on out from the clean out towards my neighbors house. Its all downhill to him. Lol
 
You can always tunnel under the slab from the outside and repair the plumbing underneath.

Your first isue is the slab moving, do you live in a area with shrink swell soil conditions? Around here (Texas coast) we have clay areas and sand areas, when concrete slabs fail home insurance covers most of the cost. I know everyone does not have insurance however the steps are still the same.

If the slab is moving and the plumbing is not leaking yet then you will be repairing the plumbing more than once. If the plumbing is leaking then repairing the plumbing will address the slab failing issue but will not fix the slab.

I suggest calling 3 different foundation repair companies that give free quotes, you will probally get 3 different recommendations and an education on what to look for.

Cracking at the exterior beam means the exterior load bearing wall is settling and you should inspect all the way around your house for other potential problem areas.


Full disclousure; I am a Plumber
 
I'd investigate that slab first. Until you understand what's going on with the slab/foundation, there's not much point in putting a bandaid on the plumbing.
 
Yes the cause of the plumbing issue will have to be addressed. Just by looking at the brick around the house there are no cracks anywhere. No cracks in the sheetrock or gaps in the trim. I wont know for sure if the slab is cracked until we take up the carpet in the back bedroom. House looks the same as when it was built 22 years ago.
Certain areas near me have had severe issues with foundations moving. None of the houses built close to me have had issues. The soil types change over the ridge from me.
My insurance has an exclusion for earthquakes and something about ground movement. Not really sure what they mean by ground movement. Im in Mississippi so the earthquake thing is not an issue.
My parents and my inlaws have both had their slabs jacked up. They both had bad cracks in the brick around their houses. Both houses were built under a hill. Pretty sure that had something to do with it.
 
Socsmm6 said:
Yes the cause of the plumbing issue will have to be addressed. Just by looking at the brick around the house there are no cracks anywhere. No cracks in the sheetrock or gaps in the trim. I wont know for sure if the slab is cracked until we take up the carpet in the back bedroom. House looks the same as when it was built 22 years ago.
Certain areas near me have had severe issues with foundations moving. None of the houses built close to me have had issues. The soil types change over the ridge from me.
My insurance has an exclusion for earthquakes and something about ground movement. Not really sure what they mean by ground movement. Im in Mississippi so the earthquake thing is not an issue.
My parents and my inlaws have both had their slabs jacked up. They both had bad cracks in the brick around their houses. Both houses were built under a hill. Pretty sure that had something to do with it.
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0% chance of insurance covering any type of slab/foundation repair caused by settling or soil movement, unless that cause of such were a result of another even that were covered.....like a pipe bursting and washing out under the slab and causing rapid settling.


That fact that you can feel something under the carpet but not other visible signs around the house is suspicious. How long have you owned it? And chance there's a previous repair under there where someone already cut out the slab to fix the line (poorly) and you're feeling the patch?
 
bgaidan said:
0% chance of insurance covering any type of slab/foundation repair caused by settling or soil movement, unless that cause of such were a result of another even that were covered.....like a pipe bursting and washing out under the slab and causing rapid settling.


That fact that you can feel something under the carpet but not other visible signs around the house is suspicious. How long have you owned it? And chance there's a previous repair under there where someone already cut out the slab to fix the line (poorly) and you're feeling the patch?
Click to expand...
We built the house in 2002. No problems up until about 3 weeks ago. Wondered if a water line could have busted under the slab. Cant find any wet places around the house. Water bill hasnt gone up any but if it happened a few weeks ago I have not been billed for it yet.
Not 100% sure I can feel a crack through the carpet or im just imagining things. It could very well be sand the vacuum cleaner never picked up over the years. Lol
 
Socsmm6 said:
We built the house in 2002. No problems up until about 3 weeks ago. Wondered if a water line could have busted under the slab. Cant find any wet places around the house. Water bill hasnt gone up any but if it happened a few weeks ago I have not been billed for it yet.
Not 100% sure I can feel a crack through the carpet or im just imagining things. It could very well be sand the vacuum cleaner never picked up over the years. Lol
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Shut everything off and go watch the meter
 
CatWrangler said:
You can pressure test your water lines and hydrostatic your drain lines to check for leakage. Are you having problems with slow drainage or lower water pressure?
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Water pressure seems to be fine. Not sure what “hydrostatic the drain lines” is. Ill have to check on that. Everything drains good from the middle (kitchen area) of my house to the septic tank. We blew the 4” line out with a leaf blower at the far clean out. Now the toilet at the far end of the house will work for a couple of flushes until the low spot in the line fills up again.
Headed to check out my water meter now.
Edit- meter is not moving so pretty sure its not a water line causing erosion under the slab.
 
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Socsmm6 said:
We built the house in 2002. No problems up until about 3 weeks ago. Wondered if a water line could have busted under the slab. Cant find any wet places around the house. Water bill hasnt gone up any but if it happened a few weeks ago I have not been billed for it yet.
Not 100% sure I can feel a crack through the carpet or im just imagining things. It could very well be sand the vacuum cleaner never picked up over the years. Lol
Click to expand...

Is the carpet glued down?


Go rip that fucking shit up. This all has me intrigued. :flipoff2::lmao:
 
Any sign of animal intrusion around the house? Not that MS getz that cold but the warmth could have attracted something already burrowed under the house and dug out around enough to cause a belly. Or it could just have been loose soil under the pipe from when it was built that finally settled enough to belly.
 
My guess would belly from poor compaction resulting in settling. That explains your crack in the slab and your line clogging itself after use.
 
Pocahontas said:
My guess would belly from poor compaction resulting in settling. That explains your crack in the slab and your line clogging itself after use.
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But 22 years later? Kinda thinking there may be a leak in the drain somewhere causing the erosion.
 
bgaidan said:
Is the carpet glued down?


Go rip that fucking shit up. This all has me intrigued. :flipoff2::lmao:
Click to expand...
I guess i will eventually, just trying to make sure thats my only direction left to go. Lol
 
Stuck said:
Any sign of animal intrusion around the house? Not that MS getz that cold but the warmth could have attracted something already burrowed under the house and dug out around enough to cause a belly. Or it could just have been loose soil under the pipe from when it was built that finally settled enough to belly.
Click to expand...
Well there is a mole that wreaks havoc in my yard. Other than that idk.
 
Socsmm6 said:
But 22 years later? Kinda thinking there may be a leak in the drain somewhere causing the erosion.
Click to expand...

Being it’s under the slab it takes awhile for it to settle then you have the slab spanning the void, just waiting for it to settle, when it settle it’s puts pressure on the drain possibly clogging it. Usually when you have a clog it isn’t a symptom of a leak.

Could be a leak that caused the erosion and the rest of the resulting damage. Just usually when you have a leak you will have other symptoms, usually plumbing especially drains don’t fail on their own there’s a cascade of problems that lead to the final failure.

You should be able to have someone scope it and you will know 100% whats going on.
 
Pocahontas said:
Being it’s under the slab it takes awhile for it to settle then you have the slab spanning the void, just waiting for it to settle, when it settle it’s puts pressure on the drain possibly clogging it. Usually when you have a clog it isn’t a symptom of a leak.

Could be a leak that caused the erosion and the rest of the resulting damage. Just usually when you have a leak you will have other symptoms, usually plumbing especially drains don’t fail on their own there’s a cascade of problems that lead to the final failure.

You should be able to have someone scope it and you will know 100% whats going on.
Click to expand...
We already scoped it. Ran the camera from one clean out to the clean out by the septic tank. Cant see any cracks in the drain but guessing there still could be a small one. Just an 8-12’ section that holds water. Blew all the water out of the line and scoped it again. Still didnt see anything odd. Im not a plumber at all so I may have over looked something. May try to scope it again tomorrow when I get off work.
Ill get a video of it and see if anybody sees something I dont.
 
That’s a belly you need to support it from underneath inorder to fix it. Easiest is to cut out the concrete and fix and report the concrete. You can also drill holes and grout under the pipe to bring it up without cutting the floor. Less invasive but more involved and possibly not possible depending on site conditions.
 
Your slab should be on top of at least 5-inches of gravel and your abs waste line should be in a trench below that filled with gravel. All over well compacted material. At least the one I recently built under inspector eye is. The gravel can’t erode out easily and it shouldn’t move either. The abs should be in the gravel and isolated from the slab and movement. Settlement if any should occur where the load reaches bearing ie at the strip footings not out in the unloaded slab. Tear that carpet out and show us the bad spot 👍
 
CatWrangler said:
You can always tunnel under the slab from the outside and repair the plumbing underneath.

Your first isue is the slab moving, do you live in a area with shrink swell soil conditions? Around here (Texas coast) we have clay areas and sand areas, when concrete slabs fail home insurance covers most of the cost. I know everyone does not have insurance however the steps are still the same.

If the slab is moving and the plumbing is not leaking yet then you will be repairing the plumbing more than once. If the plumbing is leaking then repairing the plumbing will address the slab failing issue but will not fix the slab.

I suggest calling 3 different foundation repair companies that give free quotes, you will probally get 3 different recommendations and an education on what to look for.

Cracking at the exterior beam means the exterior load bearing wall is settling and you should inspect all the way around your house for other potential problem areas.


Full disclousure; I am a Plumber
Click to expand...
In Texas i have seen MANY slabs fail. I have never seen an insurance company cover it.

Add plumbing issues and maybe. But concrete slab failure and insurance fix… nope.

And I’ve had a slab fixed, my mom has had a foundation fixed, and my sister had a foundation fixed with plumbing repairs (as well as my cousin, but we aren’t close, so I’m hesitant to list him). All were a no-go with insurance.

My sisters house they did tunnels, every one else, cut the slab to put in the piers.

3 were on Black Gumbo, I don’t know the soil on my cousins.

Edit for Google:
IMG_8797.jpeg
 
Splib said:
Your slab should be on top of at least 5-inches of gravel and your abs waste line should be in a trench below that filled with gravel. All over well compacted material. At least the one I recently built under inspector eye is. The gravel can’t erode out easily and it shouldn’t move either. The abs should be in the gravel and isolated from the slab and movement. Settlement if any should occur where the load reaches bearing ie at the strip footings not out in the unloaded slab. Tear that carpet out and show us the bad spot 👍
Click to expand...
No gravel under this slab that I can remember. Do think thats a thing here in the south. I dont recall ever seeing it done.
 
Socsmm6 said:
No gravel under this slab that I can remember. Do think thats a thing here in the south. I dont recall ever seeing it done.
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I think that’s yankee shit.

Select fill, compacted is what’s in every home I’ve seen.
 
I had a slab home at one time
the previous owner had plumbing issues, they cut the concrete and went at it from the inside, and repoured it

all I know, everything worked from them on until I sold it 25 years later
 
Idaho shit by the way. Is your abs drain line in the slab or in a trench beneath ?
 
16” raised slab, pvc drain is under it. Cant remember if it was directly under it or buried some. From the looks of the clean outs it should be covered by at least 4” of dirt.
 
Socsmm6 I wish I could be more constructive and helpful. I am not a plumber or a concrete guy or a State inspector or a builder. I have extensive experience with structural concrete and some of that was horizontal, ie road way and am building a house on a slab. My neighbor dug the plumbing runs and I laid in the ABS waste and vent lines as described prior which passed inspection. I am not familiar with the term raised slab. If it is a slab, it is in contact with bearing material, if it's not, it's a floor. Anyways, fuck, I dont know what to say but from what I have seen, and it's one build with everyting on one chance to do it correctly, there is a right way and there is everything else. Surely there will be a flood of comments but I dont see how pouring directly on soil, no matter how well compacted is productive. Black gumbo clay was mentioned. That has to move, has to fuck up. Cheesus putting any bearing on that is just floating a load on plastic material that changes over time and with moisture. It has to shift unless it is rolled with heavy machinery at optimum moisture. The reason for "gravel" 3/4 crush, is the friction angle between the grains, interlocking if you will. The layer of gravel also dissipates the effective stress and lessens and uniforms the pressure on materials below. I see no mention of a vapor barrior. ??? I was very particular regarding my build because the slab has radiant tubing in it. Cant cut and repair it practically speaking. It may be a Yankee thing but I have watched very closely hundreds of developer build tract homes out of thousands being built. They all, 100% of them are on slabs on lean clay and are without slab or foundation problems. They all are constructed with strip footings and free floating slabs over gravel. The tubing is a least 18-inches below the original soil prior to gravel application. Our current house here was built in 2006 and I haven't found a single crack in over 1600 SF of slab that is in the garage or was exposed during re-flooring. I have never seen PVC used under slab in CA or Idaho either although I dont know why. I can not comprehend how jacking or grouting or anything additive to an existing slab will not simply crack and break it more but who knows. My guess is that the piping trench, if extant was simply shoveled "backfilled" rather than carefully filled and compacted with granular material. Over time simply settling under light load has caused the low spot as your camera runs havent found anything.

Have you pulled the carpet yet ?
 
Splib said:
Socsmm6 I wish I could be more constructive and helpful. I am not a plumber or a concrete guy or a State inspector or a builder. I have extensive experience with structural concrete and some of that was horizontal, ie road way and am building a house on a slab. My neighbor dug the plumbing runs and I laid in the ABS waste and vent lines as described prior which passed inspection. I am not familiar with the term raised slab. If it is a slab, it is in contact with bearing material, if it's not, it's a floor. Anyways, fuck, I dont know what to say but from what I have seen, and it's one build with everyting on one chance to do it correctly, there is a right way and there is everything else. Surely there will be a flood of comments but I dont see how pouring directly on soil, no matter how well compacted is productive. Black gumbo clay was mentioned. That has to move, has to fuck up. Cheesus putting any bearing on that is just floating a load on plastic material that changes over time and with moisture. It has to shift unless it is rolled with heavy machinery at optimum moisture. The reason for "gravel" 3/4 crush, is the friction angle between the grains, interlocking if you will. The layer of gravel also dissipates the effective stress and lessens and uniforms the pressure on materials below. I see no mention of a vapor barrior. ??? I was very particular regarding my build because the slab has radiant tubing in it. Cant cut and repair it practically speaking. It may be a Yankee thing but I have watched very closely hundreds of developer build tract homes out of thousands being built. They all, 100% of them are on slabs on lean clay and are without slab or foundation problems. They all are constructed with strip footings and free floating slabs over gravel. The tubing is a least 18-inches below the original soil prior to gravel application. Our current house here was built in 2006 and I haven't found a single crack in over 1600 SF of slab that is in the garage or was exposed during re-flooring. I have never seen PVC used under slab in CA or Idaho either although I dont know why. I can not comprehend how jacking or grouting or anything additive to an existing slab will not simply crack and break it more but who knows. My guess is that the piping trench, if extant was simply shoveled "backfilled" rather than carefully filled and compacted with granular material. Over time simply settling under light load has caused the low spot as your camera runs havent found anything.

Have you pulled the carpet yet ?
Click to expand...
The comments saying the Idaho way is the one right way is not correct.

I’ve built 4 homes in the south.
All with engineered slabs.
Soil reports are used to determine the extent of the piers & beams.

Select fill
Compacted
Bell bottom piers
Big ass beams.

Or… post tension (which I’ve seen done across huge subdivisions, but never been involved in the construction.
(And I would be too scared to cut a post tension slab, but that’s just because i don’t know enough about it & it seems like it could go drastically wrong.

I’ve also seen slabs crack
1950s-1980 home construction.
Scrape dirt, form & pour. That’s shit construction, and hasn’t been standard in over 20 years I can personally attest to.
(although I have to admit, that’s kind of what some of the post tension set ups look like to me.)
 
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Splib, the raised slab is just where the forms or block were built up, back filled with dirt and concrete poured on top of it. Im sure you have seen it, just called it something else.
I only mentioned it because the plumber should have had plenty of room to allow for drop going to the septic tank.
The black clay must have been mentioned by someone else. There was about a 35’ high ridge that was leveled off to build my house. Ground was good for building on. They actually built the lots on both sides of me with the dirt from my lot. Neither have had trouble with the houses settling. Same concrete guy did all 3 houses. Although he did screw up my back porch, forgot the brick ledge.
There was vapor barrier used under the slab.
Ran into something a little squirrelly last night. I was going to check to see if the water in the 4” drain would leak down. Started running water in the bathtub expecting it to eventually back up. It ran for a while but never did. Toilet still doesnt flush but will drain down eventually. It actually acts like the vent is stopped up. If I had not run the camera through the lines and found the standing water I would have definitely thought that was it.
I wish I would have took several pics of the building process. Been nice to see exactly how the plumbing was run. I cant remember at all.
Carpet is still down for now. Got to figure out when im going to be able to tackle the job start to finish. Hitting about 6 days a week at work. If I can find a leak in the septic line that wasnt caused from the house shifting my insurance agent will definitely be getting a call. No signs of the house shifting anywhere that I have found so far.
 
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