More info
Thanks again to all that replied.
There have been a lot of comments back and forth about how much a DIY'er should get involved with large projects, when to call a professional, etc. I have been reading all of them and taking it all in.
I think an important factor that has been overlooked is the capability of the DIY'er. As Terry, Cass and Leejosepho have pointed out (in a different thread, sorry), they have done plenty of DIY work too.
Also, as many others have pointed out, there are some bad trades people out there that are looking for a quick buck, get the job done and get out - no matter how the work is done. I've also seen that first hand in other people's houses. I'm not a plumber, but I like to see neat work -work that makes you think that the person doing the work cared about the job. All the pros on this board seem to follow that work ethic - do the work well and take pride in it. I can really appreciate that.
I've done a fair amount of sweating, PVC work, etc as well as lots of electrical work. I tend to be a perfectionist. I always research something if I'm working with something unfamiliar. I know my limits and I would not get into things like gas (no gas on our street anyway) or the combustion portion of my boiler.
Anyway, back to my particular question: my sewer pipe relocation. I guess I should have prefaced my question with some explanation of my intentions, capabilities, and assistance.
A good friend of mine is a GC and owns the Bobcat.
The Bobcat excavator is the X325, as seen here:
http://www.kleyn.com/item-159141
He is going to be getting the forms and concrete guys, framing the addition, etc. Since he has the excavator at our house, we decided to just find the sewer pipe so that we could be sure that lowering it to a level below the basement floor slab would be possible.
It turns out it is possible. We dug (carefully) and found the pipe and made a relative height measurement with a laser-level. At the location where we dug, we found the pipe at 88 inches below the laser level height. We then pointed the laser into a basement window and measured the relative height from the floor slab. That was 65 inches. That gives us 23 inches of elevation. With a pitch of 1/4" per foot, that should allow for about 92 feet of length. We could go closer to the street if necessary.
I rented a concrete saw last week and carefully cut a trench in the basement floor slab starting under the main stack (the main stack leaves the house through the back foundation wall about 4 feet off of the floor) and ending at the foundation wall at the side of the house. I removed the concrete and dug a little under the foundation. It is an older house, so there is no footing. It is 10-inch poured concrete foundation walls. The foundation continues 11 inches under the top of the slab.
Based on these facts there is sufficient elevation between the bottom of my foundation and the sewer pipe in my front yard well before it meets the street. The foundation being 11 inches lower than the slab means we will probably need to connect a little further out toward the street to make up the pitch.
Now, I want to hire a plumber to get the proper permits (I think the board of health is involved since it involves a sewer), install the new pipe and make the new connections. I would like to have the trench all dug out, and well as the trench in the basement all dug out and ready and have the plumber not have to worry about anything but the piping and connections to the existing main stack and the lateral line in my front yard.
Does this sound reasonable?
Here are my questions that I want to get some opinions on so that when I get a plumber or two to provide estimates, I can be prepared to make sure they are going to use the proper materials:
The main stack is CI. What kind of pipe should be used to:
a. Lengthen the stack about 4 feet from where it is now to down into the floor
b. Travel under the slab (new concrete will be poured over the trench when complete) about 20 feet to the foundation wall
c. Travel about 60 feet under ground and connect to the existing fiberglass sewer pipe
Also, what kind of coupling should be used to connect the new pipe to the existing fiberglass pipe? A fernco? Are they okay for underground installations?
Obviously I will suggest (if the plumber doesn't) that a couple of clean-outs be installed at appropriate points as well.
I have attached some pictures. The main stack seems typical of what I've seen posted on this board. There are two toilets (obvious from the large CI fitting). The copper drain coming from the foreground is from the tub/shower.
This is a ranch house, so there is no second floor. The main stack extends all the way through the roof as a vent, as I believe is typical.
I know that using something other than CI to extend the stack down to the floor may require bracing of the stack.
Any ideas of cost for this kind of work? The outside pipes will be about 4-6 feet underground.
Thanks for any suggestions you can make.
And, I'm sorry for the long length of this post.