Pouring slab over septic line

[muddstopper]

I think the first thing you should do is findout from the building inspector if its even legal. I have friend who is having a dispute because building a deck over the drain line to the tank on an empty doublewide trailer. When the inspectors checked it out, they condemed the building making it unrentable until either the deck is torn down or the line is moved. Of course I dont have all the details, but it sounds like a situation to avoid if possible.

 

[ray66v]

I think the first thing you should do is findout from the building inspector if its even legal.

That should always go without saying.

Don't forget, a lot of us on TBN live where their aren't any building inspectors. :thumbsup:

 

[snowjoker]

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?

How far from your tank is the leechfield ? you do know there is a Distribution box at the end of that line.. I personally think your playing with fire doing it over your line. With footer, base, etc...What good would be putting a line next to it that is also buried ? Nothing ! you know you just cant put a line in next to it without proper grade to the D-Box. Your best bet is to call a contractor who does septic systems and have them take a look at it and let them make suggestions . We are going here on no diagram or pictures on the exact specifics..

 

[deere317]

Don't build over it! Contact a licensed septic installer in your area and find out the codes. Here in SD the tank and drainfield must be 20 ft from all structures and drainfield must be between 1 and 4 ft deep. Perforated pipe coming out of the tank will be dumping liquid under your slab every time you use water in the house. what if your slab cracks? Do you want sewage smell in your shop?(not to mention dangerous gases) I would look into routing a new drainfield around the slab and abandon the line under it. Better to spend a little more now than a lot more later!

 

[edlegault]

The frost line in Vermont must be down at least 36 inches. Which means the footers for the building will be at least that deep. Make sure the septic feed line is at least that deep or you might have to make a hole to pour concrete footing around the line (leave a "hole" around it). Personally, I would dig out the septic line to make sure there are no pre-existing cracks in it. Then lay down a "spare" line parallel to it for future use. Then pour the slab with footings, but do not pour cement directly on the pipe. I would put some sand and maybe rigid foam insulation on top of the pipe for cushioning.

 

[davedj1]

He's just doing a slab, he will be fine pouring over it.

 

[rynovt]

Just to answer a few questions...

The slab will either be a floating 6" slab or a thickened edge "alaska slab". The whole septic system is brand new so I'm hoping to have no issues anytime soon. Just to be clear....I'm not pouring a slab on my leachfield, only considering pouring the slab over the pipe that runs from the tank to the leachfield. I'll be at least 50 feet from my tank and 75+ from the field. The line is at least 4 feet deep.

One issue that many have mentioned is to ensure proper compaction under the slab. Good points since most of this will be on a 1 year old gravel drive and some of the slab will be on fill that I'm adding. Not sure how to guarantee proper compaction but guess I'll have to let excavator pound the snot out of it.

 

[ray66v]

The line is at least 4 feet deep.

At least in my area, and based on my experience, that would be unusual.

I have never seen a discharge line that was not set up to feed the tile field by gravity. So they generally are not very deep in the ground. Unless the terrain happens to rise steeply over the top of it, as it runs to the field?

I guess it's possible there are lots of variants I have not seen.

 

[rynovt]

Yes...that is correct. There is a vertical rise between the tank and the field in this spot.

At least in my area, and based on my experience, that would be unusual.

I have never seen a discharge line that was not set up to feed the tile field by gravity. So they generally are not very deep in the ground. Unless the terrain happens to rise steeply over the top of it, as it runs to the field?

I guess it's possible there are lots of variants I have not seen.

 

[Hiltz]

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 wouldnt hurt a thing to pour over it. Its the same construction for instance when you pour a basement. Any plumbing in the basement that has a bathroom, kitchen sink or dishwasher, the drains are run under the slab. Heck even if the basement has a scupper drain the pipe is run under slab. Ive been in construction for over 40 years but this is still my humble opinion. Cheers