Just installed a outside clean out for our main sewer drain. While doing this, discovered the old main drain (cast iron) was cracked all along the top ridge. We replaced the entire length of exterior cast iron with a boot hooked up to the new pvc drain with the clean out and then into the main septic. We replaced as far back under the foundation as we could for the immediate time being.

Next problem. Kids have a full bath that drains towards the master bath that drains out to the septic. Kids toilet/shower backed up several times since moved in. Could not clear from inside, thus installed the outside ground clean out. Tried to clear from outside - my little line doesn't go as far back to the clog. Water runs no issues but as soon as we tried to flush toilet paper - clogs. My thoughts - roots or broken pipe. I cannot afford to replace pipes just yet. Need about a year before we can do the major overhaul plan - but that is the plan.

My question for the meantime - We want to clean out the roots for a temp fix and continue to use both bathrooms for the next year or so. But we are noticing ceiling cracking at the seams and at the ceiling molding. I am assuming it's from the humidty in the pipes getting to the soil under the house. (Brick house and no cracks outside and no repair cracks anywhere (yet)) If that would cause too much foundation damage, then would using just the master bath for the next year and not cutting or capping off the kids drain line - would that still allow too much humidity to the crack under the house? Our master bath is literally about 5 feet off the area where we replaced the outside and added the clean out.

Hope that's not confusing. Thanks for any help!

If there is a crack in cast iron pipe, than there is an opening for roots to get in and grow. Yes, paper will clog main sewer filled with roots faster than grey water. They sell all kinds of root killers for this purpose: you pour the chemical into toilet and flush it down the drain. But it is only a temporary solution. In the meantime, I suggest you go to Home Depot and rent a big snake. Snake the line all the way to the street using your new clean out. You can buy time by doing it few times of year, but keep in mind - once roots get in, they are there to stay. So eventually , you will have to replace entire pipe. Lastly ,the cracks in the ceiling cracking have probably very little to do with your sewer line - but yes, could be part of the problem. If you have bathroom on the second floor than investigate upstairs for leaks. But I think it is probably more wood aging, house settling or seismic activity that shows with cracks in walls and ceilings.

Hope that helps

Milo