Saturday, July 24, 2010

Main Sewer Line Replacement

About a year ago, our sewer backed up.  Needless to say, it was a mess and at after-hours roto-router pricing, costly to deal with.  We have a cleanout under the house for this sort of situation, but it being the old style cast iron, was rusted closed.  The plumber had to go through a waste stack in the roof.

I watched the plumber work and thought if it ever backed up again, I would do it myself at reduced cost.  I went under the house, reamed out the lead solder that held the cleanout plug and put in a rubber gasket - something that I could easily remove if need be in the future.  About six months after the original cleanout, our sewer was backing up again and so I went to Home Depot and rented a roto-router.  The process was quite simple, but back breaking, dirty work since the Home Depot routers while electric, do not have a self feeder mechanism.  My sewer backed up 2 more times in the following six months, so I decided the best bet was to open up the main sewer line and take a look.

What I discovered was that our sewer in the front yard was a clay design: composed of 4' sections with a hub and bell style connection, concreted together.  While there were fine roots attached to the hubs, the weak points, the main culprit was a 1" break where the sewer line started to drop down the hill in our front yard.

Trenched and ready to go.  The narrow pipe in front is the
1" copper main water line.  The 1" break in the clay sewer is in the
middle of the photograph.

 Here is a close up of the 1" crack just below the hub.  I cleared away the
roots to investigate.

I ran down to Home Depot to gather all the supplies I needed:
  • 1 - 8' length of 4" ABS pipe
  • 1 - 4" Fernco Flexible Coupling (both sides equal size for the ABS to cast-iron street connection)
  • 1 - 4" Fernco Flexible Coupling (one side larger than the other to connect the 4" clay to the 4" ABS)
  • 1 - 4" 1/8 bend elbow
The following I already had:
  • sawsall with carbide tipped blade (these will cut through cast-iron and clay)
  • hammer
  • ratchet set (to tighten the hubs)
The first step was to break the clay out with a hammer.  I broke up to the point above the crack where roots where infiltrating.  Next, I removed all the broken pipe down to the point where the clay pipe connected to the cast-iron street connection at the sidewalk.  The clay was originally connected to the cast-iron with a rubber coupling.  I removed this and stuffed the cast-iron end with a towel to prevent dirt and soil from clogging while I worked.

The root mass inside the broken clay pipes.

Next, I used my sawsall to cut a straight, clean cut on the existing clay sewer.  There were too many roots, so I cut again above the next clay hub.

Sawsall with carbide blade.
After cutting the clay pipe with the sawsall.
The root mass can be seen.  I ended up cutting above the next hub.

All that was left to do was to tie in the new pipe.  I first cut two pieces of ABS to the proper length.  Next, I tied in one piece to the clay with the Fernco rubber coupling.  Then, I added the elbow and the second piece to the elbow. Finally, I connected the ABS to the street with the second Fernco rubber coupling.  Since this was a temporary fix, I did not glue the elbow.  To ensure that everything was leak tight, I took my hose and ran water at the cleanout and checked for leaks (in the process of digging out the line, I discovered a buried clean-out where the sewer came out from under the house) 

The roots are on the left.  Once the pipe was broken
they came out in one mass.

New connection, tested and with some wood stakes to stabilize.
The copper line above the pipe is the 1" main water service to the house.

The process was surprisingly easier that I expected and orders of magnitude cheaper than hiring a plumber.  Within the next week or so, I hope to rip out all the rest of the clay sewer pipe and permanently tie in the brand new sewer line.

For Fernco couplings see here.  If you live in the area, for additional plumbing supplies, help and advice, I would highly recommend Red Supply.  They are only open during the week.