How to resolve this septic outflow and parking issue

mcmxi

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About 2 years ago I dug out close to 40 yards of dirt and rock with the BX to double the size of the parking area next to the house before a company came out and asphalted about 9,000 sq. ft. for me. In hindsight I should have dug out another 40 yards to triple the parking area but it was slow going with the BX so I didn't really think about doing any more than I did. Once I got the MX I decided to revisit the project and made quick work of the bulk of the dirt removal.

I knew the septic tank was close but didn't know where the outflow to the drain field was. In the spring I found the concrete access cover that was buried under 12" of dirt and replaced it with a riser. The issue now is that I want to use the dirt area shown below for parking a trailer and possibly vehicles but the blue pipe is only 4-1/2" below level grade (referenced to the asphalt) where it enters the concrete septic tank.

Does anyone have any ideas on how I can protect the pipe and still put gravel down once I remove some more dirt such that I can drive on it without crushing the pipe? I was thinking that I could trench around the pipe and set it in concrete with some rebar parallel to the pipe for support. Maybe bring the concrete up to the same level as the asphalt and then put 3/4" gravel down that's level with the top of the asphalt and concrete.

A more expensive approach would be to buy a section of 8" heavy walled pipe and slit it the entire length and lay one half over the plastic pipe and put gravel over that.

I'm all ears if anyone has any suggestions. Thanks.

parking_02.jpg


parking_01.jpg
 

jimh406

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I’m not sure I really understand what your situation is. However, I can tell you what my septic system looks like. They added risers to my septic tank as well. We have asphalt between it and the drain field. It seems to work just fine. Btw, we didn’t add the asphalt. It was already there.
 

arto98607

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I bet your county would be interested to know more about your project....
 
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GreensvilleJay

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wow, kinda flirting with disaster,as the green pipe goes 'right', under the pavement !
to protect the pipe, you could dig trenches beside the pipe BELOW frost level (4' here...),pour pads, then 2 walls, maybe 2-3" above the pipe.motor on some thick concrete 'patio stones' or pour a slab. Besure clear stone totally surrounds the pipe. You NEED access to the pipe, one day...... be sure to take pictures,place 'locaters' where the pipe really is,say a 'penny paver' to the far right of the pavement, hopefully to warn anyone that there IS a pipe down there,so don't dig a hole for a tree...stake for a tent, etc....
if possible park a light trailer over the pipe NOT a Mack truck....
 
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NCL4701

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Good advice from GreensvalleyJay. If you go with that plan you might consider putting wire in the slab for the lid to make sure it doesn’t ever collapse.
 
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dirtydeed

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You're over thinking this. Honestly, I think you're fine. I would NOT disturb the ground around the pipe any more than you already have. If you need a parking pad, add some modified stone and tamp it in.

One suggestion would be to keep your parking pad about a foot away (to the right) of the tank. I'd be more worried about some wingnut backing onto the tank lid. Your stone would be plenty deep about a foot to the right of the tank to park anything you wanted there.

You're creating a parking pad, not a highway.
 
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D2Cat

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Yep, do like dirtydeed suggested. If you're really worried about that not being enough to support a load, put a piece of steel a couple feet wide over that length. Could be 1/4" plate, but it would distribute the load like wide tracks on a crawler. It would also protect the line from someone not knowing it was there, and be easy to locate with a metal detector.
 
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mikester

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You need to tell yourself "I am going to rip up the driveway and parking pad to replace this pipe and septic one day. That day will come sooner than later."

Plan accordingly.

Do yourself a big favour and clearly mark the pipe location now, take measurements with respect to landmarks and plenty of photos at different angles.

The septic guys will tell you NOT to drive on the weeping bed even with a lawn mower. Putting a parking lot on top of your weeping bed is never a good idea. Too late now!
 
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mcmxi

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wow, kinda flirting with disaster,as the green pipe goes 'right', under the pavement !
to protect the pipe, you could dig trenches beside the pipe BELOW frost level (4' here...),pour pads, then 2 walls, maybe 2-3" above the pipe.motor on some thick concrete 'patio stones' or pour a slab. Besure clear stone totally surrounds the pipe. You NEED access to the pipe, one day...... be sure to take pictures,place 'locaters' where the pipe really is,say a 'penny paver' to the far right of the pavement, hopefully to warn anyone that there IS a pipe down there,so don't dig a hole for a tree...stake for a tent, etc....
if possible park a light trailer over the pipe NOT a Mack truck....
The 3034 pipe under the asphalt (37 linear feet) is supposedly encased in Sch. 40 pipe.
 

mcmxi

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You're over thinking this. Honestly, I think you're fine. I would NOT disturb the ground around the pipe any more than you already have. If you need a parking pad, add some modified stone and tamp it in.

One suggestion would be to keep your parking pad about a foot away (to the right) of the tank. I'd be more worried about some wingnut backing onto the tank lid. Your stone would be plenty deep about a foot to the right of the tank to park anything you wanted there.

You're creating a parking pad, not a highway.
My plan is to place concrete retaining wall blocks the length of the parking pad maybe four courses high and backfill with dirt. The blocks are 8" deep and have a 3/4" locking overlap so that would put the base of the retaining wall about 12" out from the base of the septic tank.

I agree that this is not a highway, just a simple parking area. My only concern is crushing the existing 3034 pipe so anything I can reasonably do to reduce that possibility is a good thing. Thanks for the feedback.
 

RCW

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Following dirtydeed's advice - -

It's been a long time since I was dealing with sewage systems, but any lines put under a driveway/parking lot, etc. were schedule 40 if my memory is right.

Pipe installed same way as usual, just different material.
 

dirtydeed

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Most of the issues I've seen in this scenario involve the "grouting" seal inside the tank leaking (loose pipe), or the pipe actually shearing right outside the tank. That usually happens when installers simply backfill without tamping in lifts.

The "soil" in your picture looks like really hard ground... upon first glance, I actually thought it was cement.

I think your plan is solid.
 

mcmxi

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Following dirtydeed's advice - -

It's been a long time since I was dealing with sewage systems, but any lines put under a driveway/parking lot, etc. were schedule 40 if my memory is right.

Pipe installed same way as usual, just different material.
The sketch I found of the septic system dating back to 1992 was signed by an inspector and indicates that the 4" 3034 sewer pipe was installed inside SCH 40 pipe for 37ft. So at worst I could buy a 12ft to 15ft piece of 6" SCH 40 pipe, cut out the 4" 3034 pipe showing, install the SCH 40 pipe into the tank, slip a new section of 3034 into the SCH 40 and glue it into the existing line. That would end up costing around $1,000 or a little less.

layout.jpg
 

mcmxi

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The "soil" in your picture looks like really hard ground... upon first glance, I actually thought it was cement.
It's lifeless, pulverized rock formed over millions of years of glacial activity. It is very hard and solid ground with virtually no moisture in it. It's one of the reasons why my house doesn't have a walk-out basement and the septic tank isn't very deep. Digging up here is a rock fest that really tests the equipment being used.
 

RCW

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The sketch I found of the septic system dating back to 1992 was signed by an inspector and indicates that the 4" 3034 sewer pipe was installed inside SCH 40 pipe for 37ft. So at worst I could buy a 12ft to 15ft piece of 6" SCH 40 pipe, cut out the 4" 3034 pipe showing, install the SCH 40 pipe into the tank, slip a new section of 3034 into the SCH 40 and glue it into the existing line. That would end up costing around $1,000 or a little less.

View attachment 66039
Funny - - I have a VERY similar sketch of mine that I did....

Yeah - - a hassle to retrofit to sch 40.

I wasn't necessarily advocating to change it out. Only my recollection.

It appears to be at the edge of the planned parking area. Limited traffic may not have any affect, but I'm not sure. It's just a parking spot, not a commercial parking lot.

Honestly, if from new, I'd do sch 40. But given current site conditions, I'm 50/50 and could go either way.....leave it be or go through the effort to replace with sch 40.
 

GreensvilleJay

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whew... so the real stinky pipe is INSIDE the green one ! I was concerned about frost heav/ho cycles with weight on it.....not nice to break a joint,but it sounds like it's already 'protectect'. I would think the joint at the tank outlet would be the first to break. Sure glad you have a diagram of what's where !!!

A local guy sold off a building lot, then sold his house. new guy building on the lot, tore up an 'old septic bed'....no big deal EXCEPT it was actually the bed for the 1st house...oopsy...
 

mcmxi

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whew... so the real stinky pipe is INSIDE the green one ! I was concerned about frost heav/ho cycles with weight on it.....not nice to break a joint,but it sounds like it's already 'protectect'. I would think the joint at the tank outlet would be the first to break. Sure glad you have a diagram of what's where !!!

A local guy sold off a building lot, then sold his house. new guy building on the lot, tore up an 'old septic bed'....no big deal EXCEPT it was actually the bed for the 1st house...oopsy...
No, the green pipe is the 4" 3034. You can't see the SCH 40 sleeve since it's under the asphalt. They obviously sleeved the 3034 wherever vehicles would be passing over it. One solution will be to figure out the smallest (I.D.) SCH 40 pipe that the 4" 3034 will fit inside, then buy a 20ft section and sleeve the 3034 from inside the septic tank out 18ft and weld it to the existing sleeve.
 

GreensvilleJay

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yeesh, don't take much to cornfuse me these days...I was thinking pipe inside a pipe...sigh
Since the green pipe IS the 'stinky' pipe, I would 'protect' it,especially since it's real close to the surface. Any weird weather with bad 'freeze/thaw' cycles could move it,specially since some is under blacktop...one end could move the other not, oospy...stinky....trouble.