Tunneling under house to access sewer pipes

[DanG]

I think you misheard. I'm sure they referred to a vacuum excavator. Here is some information:

Flowable grout is cement and sand with a high water content. It is usually made up to test between 600 and 900 psi. It does not require compaction and will fill up spaces just as water would avoiding settlement and voids.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) [e-mail]

[miamicuse]

I need to have a sewer line repaired and one of the options is to tunnel under and the spot is about 5 feet from the exterior wall.

The company provided an estimate to dig using a "vaccon truck". Did a search and cannot figure out what this is, is this a mini-horizontal driller?

After the line is repaired, they said they will back fill with a "non-exacavatable flowable fill". What type of material is this? Is it plastic? If they run into a footing, do you know what is a standard procedure? Break the footing there to get through, or go under the footing? Will the back fill material be able to fill the void ABOVE the footing line?

Thanks,

MC

[miamicuse]

DanG:

I did some search and found one reference where one guy was selling a "vaccon truck" here is the link:

may be it's some high tech stuff? I will call the company to find out. I just want to make sure it's not something that will chew up the bottom of my house and cause a sink hole...

If they tunnel under the house, and go under the footing, there will be dirt above the footing line that they need to exacavate to access the pipe which I don't think they can they can back fill because you can't back fill "up". I am not sure I am saying this right, but without some sort of pump to pump dirt upward how can they back fill the void below?

MC

[miamicuse]

Thanks.

I did. Unfortunately the problem occured near an elbow so nothing can be done.

MC

[Rick]

footing line?

You might want to get an estimate from a company that does pipe bursting too

[Blue]

Curious what the symptoms of your under slab plumbing leak are?

[JimL]

To repair an elbow in my sewer line, I rented a jackhammer and dug a

4 foot deep hole in my kitchen.

If those tile could talk....

[Chip C]

When you're in Rome, top-post like the Romans.

I think the excavation probably will be some kind of hydro-excavating. Picture a BIG pressure washer and a BIG wet-vac and you get the idea. Won't damage pipes, roots, concrete. Sink-hole? hmmm. Ask them if their insurance will cover cracks in your floor or tile.

DanG's guess is as good as mine, I think you'll find they can back-fill "up" just dandy. My concern would be the "non-excavatable" part. If they fill their hole with a big concrete blob, you're never going to be able to get back under there the next time this happens. What then?

Chip C

miamicuse wrote:

[miamicuse]

Just a partial blockage. But then a subsequent video inspection (which cost $500) revealed the line break.

MC

[miamicuse]

Kitchen hole digging is out.

My wife vetoed it. Did not want to:

(1) Ruin the tiles - no replacement. (2) Have "yuck" or cockroaches coming up the kitchen floor. (3) Deal with dust and debris from the digging. (4) Remove/Replace cabinets that are sitting on the problem spot.

She rule the kitchen so I have to fix it from the outside.

MC

[Matt]

It's not a 'vacoon' truck - it's a RACOON truck. Basically 100 to 200 racoons (the more racoons, the more money) all harnessed together. They can dig out pretty much anything.

[Edwin Pawlowski]

She will relent if the sewer pipe causes enough problems. Some methods are just plain sensible, others are just plain dumb. At least consider it before going ahead with the wrong plan.

[David Alexander]

Flowable fill is a material made by a ready mix company and delivered in a mixer truck. It consists of sand, water, fly ash and a small amount of cement. It has a high water content and is very flowable. It's designed to achieve more strength than compacted dirt and is 100% compacted once it sets. It's usually designed to be excavatable with power equipment.

[rider89]

biggest concern about tunnel under footing would be that your footing is putting all the soil under it in compression from the weight of the house. when you tunnel under, x square feet of footing soil will have that compression removed, thereby transferring load to the footing to each side of the tunnel. if the soil under the footings is already of questionable stability, you might get some settling. if you were going through the foundation wall, the concrete could probably absorb the load change without problem.

bill

[BocesLib]

Matt; When you smoke those cigars, make sure to unwrap the plastic off them first....

[miamicuse]

Will it expand after being apply? What is the chance of it cracking the PVC pipe as it cures?

So after it sets it's like concrete, in the event more repair is needed they will need a slugehammer?

Thanks,

MC