1/8th inch pitch acceptable ? Garage toilet

[Brendan Poirier]

I had the sewage line ran to my garage from the septic tank. I really want to put a toilet in the garage as it is detached. The location I want to put the toilet is 21 feet from where the sewage connection enters. The sewage connection will be 1.5" under the bottom of the concrete slab. So If I run the 20ft section like in the drawing, the top of the pipe will be incased in the bottom of the slab by about 3/4'' at the most for about 8ft. Here we use ABS pipe. My question is if it is okay for the ABS to be partially in the concrete. Since the 90 degree elbow for the toilet will not be flush with the finished slab, I will be putting the toilet on a raised platform. I have no problem doing this as it is for a garage. Let me know if my drawing makes sense/will work. As far as code here we are allowed a 1% slope. I could even reduce the drain line to 3" if it will still work and it will also be slightly less in the concrete.

 

[Jeff H Young]

its a bit nit picking if you are encroaching beyond the minimum coverage of concrete I suppose the answer is No, Yea I've done it but never in a Garage with cars driving over

 

[Sponsor]

 

[Brendan Poirier]

its a bit nit picking if you are encroaching beyond the minimum coverage of concrete I suppose the answer is No, Yea Ive done it but never in a Garage with cars driving over

it will be 1ft from the wall, no cars will be driving over that specific part of the floor

 

[Brendan Poirier]

its a bit nit picking if you are encroaching beyond the minimum coverage of concrete I suppose the answer is No, Yea I've done it but never in a Garage with cars driving over

also maybe i didnt explain myself properly. The top of the pipe will be 3/4 into the Bottom of the concrete, not the top. Over top of the pipe there will still be 5" of concrete

 

[Jeff H Young]

whatever you plans call for minimum or inspector says they can get pickey

 

[Tuttles Revenge]

4" pipe is allowed to run at 1% / 1/8th per foot.

 

[Brendan Poirier]

4" pipe is allowed to run at 1% / 1/8th per foot.

what do you think about the top of the pipe being 3/4" into the concrete ?

 

[Tuttles Revenge]

We see it a lot when stretching to the ends of grade in the same scenario as yours.. if you have a 5" slab it won't make any difference at all. just cover the pipe so there is no direct contact to the concrete. If it gets embedded a lot it will definately crack the concrete and you will always know where that pipe is.. but all slabs eventually crack anyways.

 

[Jeff H Young]

I have to run 1/4 inch fall but the OP says in his area (assuming Canada) allows 1 % aka 1/8inch . I agree personally wouldn't sweat the 3/4 inch encroachment but there is a slim chance inspector might say something, When we have specs that say minimum standards the inspectors can hold you to that

 

[Reach4]

IPC allows 1/8 slope for 3 inch or bigger
UPC seems to allow 1/8 inch slope for 4 inch at times.

Chapter 7 Sanitary Drainage: Sanitary Drainage, California Plumbing Code 2019 | UpCodes

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708.1 General

Horizontal drainage piping shall be run in practical alignment and a uniform slope of not less than 1/4 inch per foot (20.8 mm/m) or 2 percent toward the point of disposal provided that, where it is impractical due to the depth of the street sewer, to the structural features, or to the arrangement of a building or structure to obtain a slope of 1/4 inch per foot (20.8 mm/m) or 2 percent, such pipe or piping 4 inches (100 mm) or larger in diameter shall be permitted to have a slope of not less than 1/8 inch per foot (10.4 mm/m) or 1 percent, where first approved by the Authority Having Jurisdiction.

 

[Jeff H Young]

foreign country , the op said they allowed 1/8 inch so I'm trusting him. it seems his question was about the concrete