Sewage pipe relocation question

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tviapiano

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Hello. We are in the process of putting an addition on our house. Unfortunately, the sewer line from our house to the street runs right though the area we want to build on. The sewer line runs out of the back wall of the basement at about chest height, travels around to the side of the house, and out to the street. What we want to do is send the pipe straight down into the basement floor slab, cut the concrete and run the pipe out the side of the house and then pick up the sewer line on the side of the house.
(Plus, this will allow me to easily install a utility sink in the basement)
I have the sewer plan of my street that the town provided. The plan indicates that my house has a "Sill" of 167.46.

We have located the pipe on the side of the house by digging a hole where we thought the pipe was. It appears to be a fiberglass pipe of about 5-6 inches in diameter.

My two questions are:

1.) What does the Sill mean? Is that the elevation above sea level that the sewer pipe exits my house?

2.) What kind of pipe is recommended for replacing the line when I locate it under the basement floor slab and then run it out to connect to the existing pipe? How should a connection between the new pipe and the fiberglass pipe be made?

Thank you very much for your help.
 

Jimbo

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Well, I don't do construction, so I am just taking a stab here: Elevations on plot plans etc. are called out in feet above sea level, so there is always a common reference. For example, the city would also know the elevation of the main below your street, so then the plan lets you know what slope is available from your house to the main.

The sill in common parlance is the base of the first floor walls atop the foundation, but I do not know if that is the reference you have.

As far as your plans, itf I understand what you are askinf, it seems that lowering the exit from your house would entail completey redoing the lateral all the way to the street, or at least to a point down slope from the new exit point.
 

SRdenny

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The plumbing portion of your project calls for a plumbing professional. I suggest you hire one who is locally established. Our answers, without observing site conditions are only going to be educated guesses at best.
 

tviapiano

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Thank you to all that replied.
To answers everyones' questions/comments:

Jimbo: Thanks for the Sill explanation. I wasn't even thinking that the sewer plan would reference the Sill in that way, but that makes sense. I thought it was some kind of reference to the elavation of the sewer pipe itself, not the building structure.

srdenny: I am going to hire a plumbing professional, however, I have free access to a medium-sized bobcat digger and someone who knows how to operate it, so I wanted to do the initial investigation work as far as where the pipe goes, the elevation, etc. without having to pay big $$ for someone else to do that. Once I know where everything is, I can then bring in the pro to assess the situation and do the work.

As Jimbo pointed out " it seems that lowering the exit from your house would entail completey redoing the lateral all the way to the street, or at least to a point down slope from the new exit point" - Exactly, that is what I intend to have done. I'm not a plumber, but I do know that the sewage pipe has to have a pitch of 1/4" per foot, and obviously that is what makes the waste flow out to the main under the street.
 

Gary Swart

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It seems pretty obvious that you first must find out if the city sewer is deep enough to allow your new line to come from below your basement floor. I wonder why the original builder didn't put the drain below the basement level and ran it out where he did. If we assume for the sake of discussion that the sewer main is deep enough for your project, then you have a huge job of digging if you are going to use a front loader. This would be more in the area that a backhoe would be used. As others have noted, a local professional should be in your immediate future. Not much point in drawing plans if you can't get the sewer line deep enough.
 

tviapiano

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Thanks Gary.

Yes, from the sewer profile plan I have, the sewer in the street is deep enough. The question is where in the line between my house and the street main is the line deep enough - that will be where the pipe is replaced up to.

The house was built in the 1960's, and I have a copy of the permit for the sewer connection from 1979 (with a very rudimentary hand drawting), so the theory is that it used to have a septic system in the backyard before the town sewer was available.

I should have clarified, but the bobcat has a backhoe attachment on it - I would not have attempted this with a front-end loader...
 

Leejosepho

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tviapiano said:
... from the sewer profile plan I have, the sewer in the street is deep enough. The question is where in the line between my house and the street main is the line deep enough - that will be where the pipe is replaced up to.

I would begin my investigation at the street. The first thing you will verify there is the depth of the main sewer line and/or any collection box related to your own line, and that is definitely a deciding factor here. Then, you might also find out something about how your line rises toward the house.

How deep will that BobCat attachment actually dig? Also, keep in mind the essence of this I saw in a shop many years ago:

Labor: $15.00 per hour
If you watch: $20.00 per hour
If you help: $30.00 per hour
If you worked on it first: $50.00 per hour
 

tviapiano

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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.
 

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Leejosepho

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tviapiano said:
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?

That will be up to the plumber, and I can imagine s/he and the inspector are going to be concerned about proper backfilling so as to not disturb connections and elevations. Also, there might be some kind of safety issue(s) related to the depth of the trench while working/reaching down inside it.
 

Geniescience

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hey tviapiano, you are skilled at learning fast. Since you know you have to get a true plumber in soon, I know one qualified plumber in your area who is active in this site right now, GrumpyPlumber. My assessment is that the level of detail you are asking for is up to the professional who you will deal with.

david
 

tviapiano

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Update

A plumber friend of my Dad was going to do the work, but he is ending up being very busy with other jobs.

I don't know any local plumbers, so, I found a plumber on renovationexperts.com that responded to my inquiry about doing this job. He came by the house last Friday to take a look. He was very cool about me doing all of the excavation work, and having everything ready with the proper amount of sand already in the trench, etc.
He does not usually do work in my town, but he does a lot in the surrounding towns so he was going to call the town to find out any particular requirements about this job.

The one question I forgot to ask him was the pipe size. The main stack is 4" CI. The fiberglass pipe outside is 6". He talked about putting 4" PVC from the stack, down under the slab, under the foundation and out to the fiberglass where the elevations met up (approximately 10 feet from the street).

My question is: does it make sense to use 4" pipe for the main sewer line when the existing pipe outside of the house is 6"? And what about pipe material, is PVC okay for the underslab and the outside portions? I am located just North of Boston.

The house currently has 1.5 bathrooms, but we will be converting the 1/2 bath to a full bath, adding a half bath in the basement, and we want to be prepared for a 3/4 bath in our pool house sometime in the (distant) future.

Thanks again for all your input into this project.
 

Jadnashua

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As to material, the pvc is fine to be burried. As to what you town wants, you have to ask.
 
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