Plumbing newb seeks advice on rough-in

[ktulu]

Hello guys!
Just got my blocks laid for a new garage addition to my home and need to make sure I am on the right track. I had initially planned to have the plumbing rough done by a plumber but after contacting 6 "respectable" plumbers and getting no interest I have decided to tackle this myself. I had planned on doing the finish work but I wanted the reassurance that the under slab work was done correctly. After scouring the Internet and especially this site I think I have come close to the correct layout for my rough-in.

I am in Arkansas if that matters. This addition will have a new sewer line run to the street. It is 80 foot from the sewer manhole and the addition is 40 feet deep. I have attempted to make a diagram showing what I am looking at doing. This shows only the overhead view of the planned rough in that will go under a 4" slab. The upstairs will be another thread!

I have a few questions:

1) I plan on using a 4" pipe for the main line. Is that big enough? Do I have to go 4" from the sewer to the back of the addition where I will terminate it with a clean out or can I reduce it down to 2"? I think I know the answer but just curious.

2)I will have 3 90 degree elbows that will come down into 8" blocks and out. I am also filling the block so I have to get this right the first time. Any things that those with experience might be able to warn me about? Or tips on getting it right?

3)Do I need to run a vent before the clean out or is having each drain vented good enough?

4)Is 3" good enough for the pipes coming down from the upper level?

5)Is 3" good enough for the toilet on the slab?

6)Once I start going up into the walls and into the attic can I tie some of the vents together assuming I dont reduce the size? Not a big deal at this point in the construction but just curious.

I know this is a lot of questions and I purposefully tried not to use to many plumbing terms as I am sure I would screw them all up and sound like even more of an iggy than I am! Apologies in advance if I have left out any info that is required to get an accurate impression of what is planned.

If anyone needs help with Linux or Arcade stuff I'd be glad to help but when it comes to plumbing I am quite helpless!

Thanks!
T

[hj]

It will work if the building department approves it with those "flat" vents, if that is what they are. I, and other plumbers, would only do it your way if the sewer was very shallow, or the ground was rock, requiring a "flat" installation. Will the utility give you a new connection into the manhole for this? Everywhere I have been they only give one connection to a property and everything has to connect to it, and they seldom allow connecting to a manhole, (workers do not like working in them and having someone flush their toilet on them).

[ktulu]

Thanks for the reply! I am researching the exact definition of a flat vent.

All vents will go up through the roof. Should they be Ts going straight up through the walls instead of having the wye and then a 90? I think I see the logic behind that. Check my updated diagram and see if thats better. Sorry for the quality.

The city inspector said that the only requirement for adding another line to the sewer was that a licensed plumber had to do the job. I am hoping I can find someone to do it if I have everything run and ready to go. One of the only plumbers I got to actually be on sight seemed to like the idea of the manhole being there.