Pouring slab over septic line

[rynovt]

I'm hoping that some of you construction or building types can advise me on my new garage. The best place to put my garage would place the slab over the line that runs from our septic tank to our leachfield. It would cover about 24 feet of the line. I would like to pour either a monolithic or floating slab in that area. Has anyone done this? The system is brand new so I wouldn't expect having to mess with it for a long time. I do have nightmares about ever having to dig that line up once the garage is over it.

Thoughts?

 

[Kyle241]

I personally would not do this. Also are there any code issues with doing this? It can be done but that is a lot of weight on top of the pipe and all buildings settle. Also inevitably you'll need to get under there at some point and that will be a royal pain. I'm sure others will chime in as that is my personal opinion. Absolutely no other place to put the garage?

 

[Gary Fowler]

I wouldnt have a problem with putting a slab over the line assuming all the cleanouts are in place and not under the slab. You are talking about a solid line and not the field line I assume. If it was properly glued down, there is not any way for roots to get inside. Only time I ever had to dig one up was because the builder ran a trencher over the drain from house to city sewer line at my old house. I kept requiring rotorooting about every year and finely I had a plumber do a video scope on it and found the cut. @##$% contractors knew they hit it but just put a split oil can over the cut. Of course this was 30 years after the house was built and I was the second owner.
As far pressure on the line, that should not be problem either as long as the line is at least 12" under ground you could run just about anything over it and not hurt it. Just be carefull with the concrete trucks when they come in if the ground is a little wet because those things do put some soil pressure down.

 

[Aguanga]

I would obviously try to avoid it. How much fall is in the line? If you have enough fall, you can relocate the line to go around the new building location. When relocating, try to keep the new allignment beyond the bottom of the footing so that it does not fall with the load bearing area beneath the footing (typically a 1:1 slope away from the outside bottom corner of the footing). If you don't relocate the pipe and all of your load bearing walls are on the perimeter, you could also dig and expose your pipe within this same imaginary load bearing area where it crosses your footings. Once exposed, assuming that it's a conventional garage structure, you'd be OK with concrete encasing the pipe for 12" on all sides. Make sure you don't "float" the pipe when pouring the concrete around it (potentially creating a high point or reverse fall in a section).
However, you could also roll the dice that you'll never have a problem with the pipe. In the future you could replace the section of pipe under the garage later using pipe bursting, but that'll probably set you back $2-3,000 if you do all of the prep work for a trenchless pipe specialist contractor.

 

[/pine]

I would obviously try to avoid it. How much fall is in the line? If you have enough fall, you can relocate the line to go around the new building location. When relocating, try to keep the new allignment beyond the bottom of the footing so that it does not fall with the load bearing area beneath the footing (typically a 1:1 slope away from the outside bottom corner of the footing). If you don't relocate the pipe and all of your load bearing walls are on the perimeter, you could also dig and expose your pipe within this same imaginary load bearing area where it crosses your footings. Once exposed, assuming that it's a conventional garage structure, you'd be OK with concrete encasing the pipe for 12" on all sides. Make sure you don't "float" the pipe when pouring the concrete around it (potentially creating a high point or reverse fall in a section).
However, you could also roll the dice that you'll never have a problem with the pipe. In the future you could replace the section of pipe under the garage later using pipe bursting, but that'll probably set you back $2-3,000 if you do all of the prep work for a trenchless pipe specialist contractor.

If it is a solid line, not part of the leaching/percolating system it would no different than any other plumbing that is normally placed under a (house etc.) slab...hopefully it is at least schedule 40 or better and not the thin-wall piping...

 

[CurlyDave]

Go ahead and cover the line.

While the most appealing solution would be to re-route the line around the garage, it is actually more expensive than necessary.

Be certain that you have left a pathway to easily abandon the line under the garage if necessary and to re-route a new line around the garage. If you take this simple precaution, you have a much more appealing way out of a seemingly intractable problem if there is ever any need to dig up the old line.

 

[hosspuller]

Another thought is to bury another line parallel to the existing line. Call it a repair line. Just make sure it's well marked and known to anybody that follows in the years to come. Perhaps markers in the slab

 

[CNC Dan]

I'm hoping that some of you construction or building types can advise me on my new garage. The best place to put my garage would place the slab over the line that runs from our septic tank to our leachfield. It would cover about 24 feet of the line. I would like to pour either a monolithic or floating slab in that area. Has anyone done this? The system is brand new so I wouldn't expect having to mess with it for a long time. I do have nightmares about ever having to dig that line up once the garage is over it.

Thoughts?

it's too be avoided if you can. But if you have to, dig in a second pipe now, with the ends capped off. Use something permanant to mark the ends so you can find it in 20, 30 years. Then if the line ever fails, you have a spare in place, no digging up the slab.

 

[Stimw]

You don't have your location posted- frost line???? Footer depth?????
You don't say what material pipe is or depth. ???
Questions that need to be answered to give an educated answer.

 

[tessiers]

Aren't many buildings that don't have some sort of burried sewer lines under them. If you have problems in the future you re route the line, depending on inverts and diatance it could get costrly but then again you could always bore under the garage if you had too. I have worked construction all my life and if it is a new properly installed line and you have adequate foundation soil bearing I say go for it.