Replacing Multi-Family Sewer Line Under Slab

[GCProp]

I own a 7 apartment multi-family building built in 1974. Sewer line is cast iron. We have clogs frequently and it appears cast is corroding. I know it's only a matter of time before I will need to replace it. Problem is, the building sits on a slab. It's also fully leased. Line runs left to right down the full length of the building, servicing each apartment one after the other until it exits the building under the right side wall. So, unless there's a new replacement method I'm not aware of, I'll be cutting up the slab inside each apartment to install a new PVC sewer line along with feeder lines to each drain (2 baths and a kitchen in each apartment). And then once new plumbing is installed and concrete poured I've got flooring to replace. So this is going to be a lengthy project. I can't envision how to get this done while tenants are living in the building. Any suggestions?

 

[Terry]

Have you camera'd line to make sure it's rotting? If it's grease, you can start with something like Bio-Clean, which is harmless to pipes but deadly to grease buildup. It turns fats into carbon dioxide.

If you're cutting slabs, some of those pipes may be several feet underground. You will be lifting up tubs for access and redoing bathrooms. There won't be any usable plumbing for at least a month, as far as I can tell.

 

[Sponsor]

 

[GCProp]

Haven't sent a camera down the pipes yet. Definitely a good idea BEFORE cutting up the slab! I have had to replace some of the cast coming out of the kitchens because of corrosion holes in the cast. The Bio-Clean looks interesting and I'll definitely give it a try before doing anything else. Thanks!

 

[Terry]

Kitchen lines seem to fail first. The chemicals that are put down them is often the cause.

 

[Supr]

what about trenchless pipe repair?

 

[Reach4]

So this is going to be a lengthy project. I can't envision how to get this done while tenants are living in the building. Any suggestions?

How about a new sewer line across the front yards or back yards? Cut each unit to the new sewer one at a time. The others use the old sewer until their turn comes. Just a thought you could discuss with your engineer/contractor.