Houston, we have a problem

[bluedog225]

What do you guys think I should do with this?

This is the 4 inch waste line from my workshop to the septic tank. The building is set on nine 20’ deep concrete piers. The septic tank is set about 6 feet down on undisturbed soil and a bed of gravel. The soil of that depth is sand with clay.

One of two things has happened. Either the septic tank is settled in, or this is differential movement between the deep foundation of the workshop and the relatively shallow foundation of the septic tank.

In anticipation of some differential movement, I had them place a flexible coupling between the pvc plumbing coming out of the septic tank and the foundation. Obviously it wasn’t sufficient for this amount of movement.

I’m going try and find a larger flexible coupling. Or I’m going to extend the PVC and reuse this shorter coupling. And see what happens.

It’s been dry. And over the seasons, I will come to find out more information about whether this is a permanent settling or if it’s going to be something I have to deal with seasonally.

I’m open to other ideas or suggestions. Thanks.

 

[cvairwerks]

The board puked on your photos, so they don't show....

 

[bluedog225]

Ok. Thanks for letting me know. Try it again.

 

[jmdirk]

Well, since you're not in the north, it's not frost heave

I'm guessing your tank moved

Has it been a particularly dry year for you? Since you have clay under the septic, it's overall properties can change significantly depending on how moist it is.

I used to work foundation repair and there was one older part of the city that was a lot of clay and never had any stormwater management, such as weeping tile around the base of foundations. Most of these were built 80-100 years ago, natural stone foundation kinds of places. At some point, the city went around an started installing stormwater management etc. Not necessarily weeping tile around the houses, but larger stormwater collections projects etc. Over the years the subsoil slowly dried out and several homes that had been there for decades, started settling. We did several underpinning jobs there as a result.

 

[carcruse]

One or more of these connectors will probably work:
https://www.fernco.com/products/flexible-couplings/expansion-joints

 

[bluedog225]

One or more of these connectors will probably work:
https://www.fernco.com/products/flexible-couplings/expansion-joints

That looks like just the type of thing I need. Thanks.

 

[bluedog225]

Well, since you're not in the north, it's not frost heave

I'm guessing your tank moved

Has it been a particularly dry year for you? Since you have clay under the septic, it's overall properties can change significantly depending on how moist it is.

I used to work foundation repair and there was one older part of the city that was a lot of clay and never had any stormwater management, such as weeping tile around the base of foundations. Most of these were built 80-100 years ago, natural stone foundation kinds of places. At some point, the city went around an started installing stormwater management etc. Not necessarily weeping tile around the houses, but larger stormwater collections projects etc. Over the years the subsoil slowly dried out and several homes that had been there for decades, started settling. We did several underpinning jobs there as a result.

It’s been dry lately. But not particularly dry this summer. This clay is of the awful. It moves a bunch