Slab toilet rough in

[Jfomtn]

I'm having new detached garage built with a toilet and sink. Will this work for toilet drain? Just trying to dry fit to see how it looks. will cut down long 3 inch pipe to fit a 3 inch flange. The right hole will have 1.5 inch vent pipe up wall and out

 

[Jfomtn]

right side will continue out to a sewage pump outside garage

 

[Sponsor]

 

[Jeff H Young]

?? no somethings wrong why are the the combi,s backwards?

 

[Jfomtn]

sorry.combi?

 

[Terry]

Combi = combination wye. A wye with 45 is pretty much the same thing.

The wye or combi should direct water and waste in one direction, downhill.

 

[Reach4]

Flow is left to right? Both combis (combination wye and 45) should send flow toward downstream.

What flow is coming from upstream?

 

[Jfomtn]

I have a sink outside the toilet room that I am having wye into the main 3 inch drain.yes flow is left to right .

 

[Terry]

I have a sink outside the toilet room that I am having wye into the main 3 inch drain.yes flow is left to right .

The wye is the wrong direction.

 

[Jeff H Young]

both fittings should flow the same direction so it looks like the smaller 2 inch is backward . can you see why it needs turned around?

 

[Jfomtn]

should the vent wye be turned the other way?

 

[Jfomtn]

hA! yes looks like poop may flow into the vent turned that way

 

[Jfomtn]

the left(upstream)sink side .

 

[Reach4]

I have a sink outside the toilet room that I am having wye into the main 3 inch drain.yes flow is left to right .

That bathroom sink (lavatory) is vented. So if that it the only thing coming in from the left, I think that can wet vent the toilet. In that case the vent in the wall would not be needed. That smaller combo doing the vent would have been the wrong way. But it would have worked.

Under IPC you can use a sanitary tee on its back for venting as an alternative to a combo, but again, that vent at the wall will not be needed.

What may be objectionable to some is the wet vent coming in line with the toilet and the toilet feeding from above. Let's see what thoughts people have on that.

 

[Jfomtn]

not the best artist.drawing of the sink and toilet drain together.so you are saying the 1 vent about from the sink about 17 feet away will wet vent the toilet also.?thanks jason

 

[wwhitney]

What may be objectionable to some is the wet vent coming in line with the toilet and the toilet feeding from above. Let's see what thoughts people have on that.

Up.codes says that TN has adopted the IRC and P3108.1, including the text "Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent."

Chapter 31 Vents: Vents, Tennessee Residential Code 2018 | UpCodes

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So if this detached garage is an accessory structure to a 1 or 2 family detached house or a townhouse, then the wye where the WC drain joins the lav drain would need to be horizontal for the lav to wet vent the WC.

Cheers, Wayne

 

[Jfomtn]

if it matters,the sink drain will come down to ground or in slab then slope horizontal to the wye that connects the lav to the wc drain

 

[wwhitney]

Apparently you are supposed to offset the WC to the side of the building drain, then have the closet flange connect to a closet bend that is pointed at a horizontal wye. That would let you eliminate the dry vent at the WC.

If you prefer to use a dry vent at the WC, you'd typically take it off before the WC drain hits the building drain (the lav coming in).

Cheers, Wayne

 

[Jfomtn]

so it should tee in more like this

 

[wwhitney]

Yes. Where the arrow represents either

(1) a closet bend under the flange with outlet pointed perpendicular to the dashed building drain, hitting a horizontal combo, or
(2) a closet bend under the flange with outlet pointed downstream at a 45 degree angle to the dashed building drain, aimed directly at the side inlet of a horizontal wye.

Cheers, Wayne

 

[Jfomtn]