Drains installed before concrete slab... myself??

[Steve_B]

The water and sewer lines are already ran onto the property on the front lawn... the house will be built roughly 40 feet back from where the sewer line tap would be

I have a total of 5 drains to be installed.... 4 of which will be in the bathroom, and 1 of which will be the kitchen sink roughly 20 feet away

Has anyone done their own drain install themselves, or is it too hard to do worrying about the correct pitch of the drain pipes in the ground?

I would like to do it myself, but it must be done right as I do not want to tear into the slab if something is not working right...

Thoughts on doing it yourself versus using a plumber???

If best to use a plumber, anyone have any idea on cost so I do not get taken advantage of

[flyingvan]

  I've done two builds now, with no professional help----didn't go with slabs, though.  I didn't think the plumbing was any more difficult than the framing, roofing, or electrical.  I just bought a book from the big box store-- http://www.hamiltonbook.com/tauntons-plumbing-complete-expert-advice-from-start-to-finish ---it was written at a comprehensive level.  One mistake I made---I made the main drain 4" pipe thinking 'bigger is better'.  It might be, but I later found out all my vents combined had to have a cross section area equal to or greater than the main drain, so I've got  1 1/2", 2", and 3" vent pipes all coming through the roof.
  Learn all you can about gluing pipe.  That is where people cause themselves headaches.  Cut the pipes square, clean up the cut, don't use too much glue, fully seat them, then give them a quarter turn and manually hold them in place for a full minute.
  If you use copper for supply, pay the extra and get type 'L' pipe.  Better yet use PEX (I didn't because a neighbor had mice chew through his.  Any mouse that can chew through copper can have it)

[alex trent]

The pitch of the pipe should not be too hard to get right over that relatively short distance. Do a lot of checking.  Most of all flush several times with paper (and I added some mashed bananas) to see if it all flows before you close it up.

1/4 inch drop is what is the recommendation for each foot.  Many say 1/8 inch per foot will do it. I worry about that a bit, but am now doing one at 1/8 because the length of the run is so long and needs to be dug by hand and I have a bit of a hill to go through so I do not want to have to dig 8 feet down.  I'll have lots of clean outs along the way.

In spite of the common idea that 1/4 inch drop per foot is gospel and should not be steeper because the solids will get left behind by the fast running water, I have one that drops 1 full inch per foot and no problems.  I hear the same thing from others.

[Steve_B]

Along the lines of installing drains before the slab....

Lets say I was goin to have an island in the kitchen with an electric cooktop on it.... before the slab goes in, could I, or should I, run a stretch of pvc pipe from near the wall in the kitchen to where the island will be underground to be able to run the electric to it and it be out of sight and harms way?

Is this feasible, and would there be ANY safety hazards with doing this?

[Rob_O]

Along the lines of installing drains before the slab....

Lets say I was goin to have an island in the kitchen with an electric cooktop on it.... before the slab goes in, could I, or should I, run a stretch of pvc pipe from near the wall in the kitchen to where the island will be underground to be able to run the electric to it and it be out of sight and harms way?

Is this feasible, and would there be ANY safety hazards with doing this?

Unless the inspector says otherwise, I'd just run 1" PVC under the slab. Run a string as you assemble everything and tape off the ends to keep concrete out

[Steve_B]

FINALLY got one plumber who says he will do the rough plumbing... sounds kind of high to me, but maybe your thoughts here....

Install the 5 drains before the slab and have the main drain line come just outside the slab is $1425

Run the main drain line from outside the slab to the sewer tap roughly 80 feet away is $575

Complete rough plumbing for drains is $2,000..... way higher then I thought it would be!!!!

I have called every other plumber in the area and no one at all wants to do it or give an estimate for it

Your thoughts??

[Alan Gage]

I did my own before pouring my slab. It was a lot of work digging it in by hand and it took a lot of careful measuring to be sure everything would come out where it was supposed to but other than that pretty painless. I did a lot of studying about plumbing before and during the process.

In the end I changed the design of my shower a little and had to move the drain over about 4". I dreaded it and spent I don't know how much time trying to come up with a way around it. Turned out to be a pretty easy process to move it.

I wrapped the drains for the toilet and shower with some foam that was probably about 1/4" thick and then wrapped layers of plastic over that to make it a bit thicker.  After the slab was poured  and the plastic and foam was removed there was enough clearance between the pipe and concrete for a flange to fit on the outside of the pipe.

Alan

[ScottA]

I recommend you get a plumber unless you are fairly confident in your ability. Underslab problems can get expensive to fix fast. Expect to pay about $600-$1000 for 4 openings including digging.