Question on sewer replacement under slab.

[Josh J]

Howdy,

I have a 50 year old home with cast iron pipes under the concrete slab. Discovered that some/all of the old sewer lines need to be replaced after having a cleanup installed and seeing a giant crack with my own two eyes. I've checked with a few plumbers and they all tell me the same thing really. Several companies have mentioned that they hang the pipes from the underside of the foundation. The company at the top of my list (based on professionalism, reviews, etc.) told me they do not hang the pipes but do support them correctly under the tunnel is filled back in. I could see pros and cons to either method. The soil here is terrible (clay), and my home has had two goes at foundation repair before.

I'm a teacher so most of this is over my head, and I'm hoping to get some insight from elsewhere on the subject. Replacing some shower stems and valve seats is about as far as I've gotten into plumbing.

 

[Geofd]

there is another method you may consider...pipe relining....I work for a lager university in boston...we have done this now 5 times....it is epensive but there is no digging
the breaks can be repaired theyput a camera down the drain ten snake or jet it then reline the finished product is just like pvc guaranteed for 50 years ….but it is expensive
just a thought

 

[phishfood]

I do not have any personal experience with tunnel replacement jobs, that just isn't done here in my area. But I have had multiple discussions with plumbers who do this type of work, and they all mentioned supporting the new piping from the foundation. They also mentioned that they had to use stainless rod and clamps.

I would be very nervous about not suspending the pipe, especially in bad soil.

 

[Josh J]

I was poking around the ICC building codes and didn't find much. Appears to me that as long as it's supported either through hangers or a tamped soil base then it is passable. As I said, I could see pros and cons to doing it either way.