Suggestions Needed! Ripping off completely and restarting!!!

[MikeGA]

I think the picture says it all, I want to rip this apart completely if needed, suggestions needed on what to do, I really don't know all the rules around venting. What has to be dry vented what can be wet vented. Besides the venting are there any other obvious code issues here. Is there another way to run this thing?

 

[MikeGA]

Ok...new question...can remove all wyes and then create a single vent from the bath sink that ties into an existing 2" dry vent? Will that take care of the toilet, shower, and laundry sink vent?

 

[Sponsor]

 

[wwhitney]

On the last question, definitely no. You are going to need 3 dry vent take offs, one for the laundry sink, one for the lav, and one for the shower (since the lav is on the wrong side of the building drain to use for wet venting the shower). Then the shower can wet vent the WC. The dry vent takeoffs have to be at the elevation of the trap, so above the slab for the two sinks. Then the dry vents can rise, and once they are 6" above the fixture flood rims, they can all combine, and connect to your existing 2" dry vent through the roof. That could happen in the upper wall framing or in the floor framing.

How about a photo of the slab, take from near the ceiling level looking mostly down, on which all you have drawn in are the bottom plates of the wood walls you will be framing in? And showing where that existing 2" dry vent is. Then we could mark up the photo with our suggestions.

Cheers, Wayne

 

[MikeGA]

On the last question, definitely no. You are going to need 3 dry vent take offs, one for the laundry sink, one for the lav, and one for the shower (since the lav is on the wrong side of the building drain to use for wet venting the shower). Then the shower can wet vent the WC. The dry vent takeoffs have to be at the elevation of the trap, so above the slab for the two sinks. Then the dry vents can rise, and once they are 6" above the fixture flood rims, they can all combine, and connect to your existing 2" dry vent through the roof. That could happen in the upper wall framing or in the floor framing.

How about a photo of the slab, take from near the ceiling level looking mostly down, on which all you have drawn in are the bottom plates of the wood walls you will be framing in? And showing where that existing 2" dry vent is. Then we could mark up the photo with our suggestions.

Cheers, Wayne

On the last question, definitely no. You are going to need 3 dry vent take offs, one for the laundry sink, one for the lav, and one for the shower (since the lav is on the wrong side of the building drain to use for wet venting the shower). Then the shower can wet vent the WC. The dry vent takeoffs have to be at the elevation of the trap, so above the slab for the two sinks. Then the dry vents can rise, and once they are 6" above the fixture flood rims, they can all combine, and connect to your existing 2" dry vent through the roof. That could happen in the upper wall framing or in the floor framing.

How about a photo of the slab, take from near the ceiling level looking mostly down, on which all you have drawn in are the bottom plates of the wood walls you will be framing in? And showing where that existing 2" dry vent is. Then we could mark up the photo with our suggestions.

Cheers, Wayne

 

[wwhitney]

You didn't include the photo view I suggested, but I marked up one of the photos to show an option. Red is 3" (or 4" for the building drain, if that's what you have), blue is 2", and green is 1.5".

On the lavatory, I show a 2" drain below the san-tee just on the basis that it doesn't make sense to put 1.5" drains under the slab, not sure if that's true; that drain could be 1.5". The vent rises up and needs to connect to your existing vent, those details are not shown.

On the shower, you didn't specify where any other walls are, so I ran the shower drain towards the exterior wall for the dry vent takeoff (which has to be vertical and stay vertical, so horizontal dry vents under the slab as you currently have are not allowed). The horizontal angles are all supposed to be 45s, not sure if I rendered those correctly. The vent comes off with an upright combo, or a san-tee on its back if space is really tight.

Then the shower drain combines with the WC drain to wet vent the WC. That's supposed to be a horizontal wye (3x2x3, i.e. 3" with a 3x2 bushing in the straight inlet), with a closet bend on the branch inlet. I'm not certain that the relative geometry of the shower drain location and the WC flange location, relative to that exterior wall, will actually allow the shower drain to end up on the shower side of the existing WC drain path. The shower drain could run longer along the exterior wall and then 45 over on the other side of the existing WC drain path, in which case the closet bend would point perpendicular to the building drain to a wye on the shower drain.

That leaves the laundry drain. Its vent comes off the horizontal trap arm with the same fitting options as the shower. Then I show the drain increasing to 2", again because it's going into the slab. The tricky part is that the drain has to pass behind the shower vent, because for the shower to wet vent the WC, the laundry has to join downstream of the bathroom fixtures. So it might be easier to keep the laundry drain 1-1/2" on the horizontal above slab portion, so it can pass behind the shower vent more easily.

Or you could pass the laundry drain around the outside of the shower by breaking open more slab, then you wouldn't have the crossing. Or you could route the shower drain under a different wall for the vent takeoff, which I could consider if you provided the wall plate locations as suggested.

No laundry standpipe?

Cheers, Wayne