Relocating laundry tray vent concerns

[Djta11]

Good morning, gentleman.

Found some termite damage, and a leaky shower curb and one thing lead to another and I’m now remodeling the 1st floor guest bathroom and laundry room on my tri-level home built in 1976-ish.

I figured since I had the bathroom walls were opened up I would move my washer/dryer from the opposite side of the wall shown in the pictures to 90d around the corner on the right so I could put both machines on the end wall and free up some much needed space in the tiny laundry room.

There are 2 full bathrooms directly above this room and this bathroom and laundry room are on on a slab. The horizontal main drain is buried under concrete but is a 4” line - but could be 3” - I’ve not dug the shower pan cavity deep enough yet to confirm. Everything shown here feeding the cast iron is threaded pvc.

Here is where I’m somewhat confused about proper venting for the washer tray relocation.

Currently, the standpipe is dry vented very close to the tray but to move it where I’d prefer, the distance needed is ~63’ to the corner and ~16’ after the turn. From my understanding of the KY code, I need a vent no more than 5’ from the standpipe‘s trap being it is a 2” pipe.

My thought was to remove the existing sanitary tee for the current standpipe, run the new drain around the corner (with appropriate washes) to reconnect to the same 2” drain. Once around the corner and within 5’ of the trap, add a 1.5” vent to the laundry drain and connect it to the existing horizontal 1.5” dry vent currently servicing the sink and washer.

My question is, can I tie the washers vent into the vertical 2” shower dry vent that services the current sink/standpipe on the left or should I extend it closer to the horizontal 1.5” dry vent where the washer discharge will feed? Essentially going straight up around where I’ve drawn “63””. I feel that would be easiest since I can manhandle the horizontal 1.5” line easier than the vertical 2” shower vent because I’m not sure how well secured it is.

Thanks in advance for your time - it’s very much appreciated.

 

[wwhitney]

Didn't quite follow your question, but your 1.5" vent from the relocated laundry standpipe san-tee should rise vertically to at least 6" above the standpipe flood rim. Then it can turn horizontal and connect to any other dry vent, again at least 6" above the flood rims of the fixtures vented.

Cheers, Wayne

 

[Sponsor]

 

[Djta11]

Didn't quite follow your question, but your 1.5" vent from the relocated laundry standpipe san-tee should rise vertically to at least 6" above the standpipe flood rim. Then it can turn horizontal and connect to any other dry vent, again at least 6" above the flood rims of the fixtures vented.

Cheers, Wayne

Thanks so much for the quick reply and sorry for the confusion - it made sense to me after proofing a dozen times but this has given me tunnel vision.

My question was, should I tie my washer‘s vent into the horizontal 1.5” vents on the left side of the pics that feeds into the vertical 2” shower vent on the right, but your response indirectly answered that question for me. It would be much simpler to attach to the vertical 2” shower vent due to the adjusted height of of the new outlet box. Otherwise I’d have to increase the height of the sinks vents to reach above the flood rim.

Any other advice you’d recommend that I add or modify before I seal it all up?

 

[wwhitney]

In the upper right of the wall, I believe that's a san-tee on its back where the two tub drains connect--that's not allowed. It needs to be a combo.

Cheers, Wayne

 

[Djta11]

In the upper right of the wall, I believe that's a san-tee on its back where the two tub drains connect--that's not allowed. It needs to be a combo.

Cheers, Wayne

You’re right - it is on its back. To clarify, you’re talking about a combo wye on the left, but the elbow on the right is fine; no need to wash the right?

Also - I’ve taken a closer look at the existing washer standpipe trap and is going to be a bear to remove the drains vertical san tee since it’s stacked on top of another. I’ll have no purchase if I remove it and there’s a shortage of reamers in town. Is it safe to cap the trap since there’s no fixture upstream or should I loop the trap back into the drain?

Thank you again!

 

[wwhitney]

You’re right - it is on its back. To clarify, you’re talking about a combo wye on the left, but the elbow on the right is fine; no need to wash the right?

The RH elbow there should be a LT90, can't tell from the picture. Changing the san-tee on its back will be a pain, and you'd have to replace that elbow anyway. You'd probably need (3) shielded rubber couplings. Plus there's the question of whether the combo would fit in that stud bay, or if you'd need to jog the left of the two drains over to the next stud bay to the left. You could instead try to combine the two drains on the vertical, although the combined drain needs to be 2" as it is currently.

Also - I’ve taken a closer look at the existing washer standpipe trap and is going to be a bear to remove the drains vertical san tee since it’s stacked on top of another. I’ll have no purchase if I remove it and there’s a shortage of reamers in town. Is it safe to cap the trap since there’s no fixture upstream or should I loop the trap back into the drain?

I don't know if leaving the trap there is reasonable or not. To remove it, you could get a rambit or fitting saver type fitting, and drill out the san-tee side entry, then plug the side entry. Or extend the side entry for your standpipe location, assuming you can fit a 2" around the two stacks.

Cheers, Wayne

 

[Djta11]

Supplies ordered and picking up the rest before the weekend. I’ll be making the changes and routes you recommended - thank you so much.

It’s also looking like I’m going to have to rework a lot more of the existing piping than expected.

I’m installing a 3 wall Maax Utile shower system and after dry fitting the tray and ensuring my walls are plumb and square, I noticed the lips on the san tees directly above the pan are about ~1/4 proud of where I need to install a shower wall - the sweeps aren’t as tight as they could be and need to be for my installation - so I need to remove/replace and rotate a few degrees. This was done to fit around the 3” stack. I see no viable way to reroute the lav vents to avoid running into another pipe aside from adding an AAV (would prefer to avoid) - besides, I have to route the 2” washer drain the already congested area, so it’s tightening up the sweeps and bumping out the wall where necessary.

I don’t have the luxury of robbing a single millimeter from the showers opposing wall because it buts up to a stairwell so I’ve got to work the pipes wall.

Thank you again for your help and hopefully I can make decent progress on it this weekend and will upload pics if anyone is interested.

 

[wwhitney]

So how is the WC vented? What is going on at the base of the 3" stack? Do you know the configuration below the floor (slab or wood floor)?

If you are going to rework all the DWV in that wall, can you steal some room from the other side (laundry side) of the wall? Not sure if that's useful, just worth considering.

Cheers, Wayne

 

[Djta11]

So how is the WC vented? What is going on at the base of the 3" stack? Do you know the configuration below the floor (slab or wood floor)?

If you are going to rework all the DWV in that wall, can you steal some room from the other side (laundry side) of the wall? Not sure if that's useful, just worth considering.

Cheers, Wayne

 

[Djta11]

I believe the toilets and the entire drain line is vented by the 2” vertical stack I’ve previously called the shower vent.

The 3” stack ties into a threaded flange and transitions to cast iron. That stack services 2 toilets and a sink.

The floor is concrete and the drain is buried about 6-8” OC. All vertical DWVs must 90 towards the laundry room behind ~16” because I can see a cast iron 90 protruding from the 1st floor slab going back into the basement floor. The house is a split level and the basement is ~3’ lower than the 1st floor where this bathroom and laundry room are located.

I can’t rob any space from the laundry room behind because the depth is barely enough to fit the w/d side by side. Even had to remove the drywall and will be replacing with 3/16” wainscoting panels and trim to hide the change in wall thickness.

One possible solution hinges on if I can tie my new washer drain and vent into the vertical 2” shower/toilet vent. I’m researching to see if that’s permissible, but it makes sense to me that since I’m already cutting into it to adjust the san tees, adding a combo wye below the highest vent connection would help shave my efforts with building around the 3” stack to go all the way to the farthest sink drain.

 

[wwhitney]

OK, it would be helpful if you could mark up your last photo with what you infer about the pipes below the slab. Based on looking into the closet flange (or with a small inspection camera if you have one) and the broken up area around the shower trap (which I assume you are relocating).

I'm trying to figure out if there's any way you can flatten the DWV in that wall so you don't have any crossings. I mean obviously there is, but I imagine it wouldn't be worth breaking open 20 square feet of slab to move the drains under the slab, so a less intrusive method.

One possible solution hinges on if I can tie my new washer drain and vent into the vertical 2” shower/toilet vent.

Almost certainly not on the drain. If the shower drain is going from the trap to just under the 2" shower vent stack, with the vent taken off the top of the shower drain, and then the drain then goes on to connect to the WC drain (which should happen before the 3" drain stack joins either of those), then the shower is dry vented and the WC is wet vented by the shower. The only thing you could drain into that shower vent (which would make the shower wet vented as well) would be bathroom fixtures (the lav), not anything from the laundry.

If you want to avoid the laundry drain crossing the shower vent, you could of course break open the slab and connect horizontally to one of the drains under the slab (after any wet venting, so after the hypothesized shower drain/WC drain joint).

Cheers, Wayne

 

[Djta11]

OK, it would be helpful if you could mark up your last photo with what you infer about the pipes below the slab. Based on looking into the closet flange (or with a small inspection camera if you have one) and the broken up area around the shower trap (which I assume you are relocating).

I'm trying to figure out if there's any way you can flatten the DWV in that wall so you don't have any crossings. I mean obviously there is, but I imagine it wouldn't be worth breaking open 20 square feet of slab to move the drains under the slab, so a less intrusive method.


Almost certainly not on the drain. If the shower drain is going from the trap to just under the 2" shower vent stack, with the vent taken off the top of the shower drain, and then the drain then goes on to connect to the WC drain (which should happen before the 3" drain stack joins either of those), then the shower is dry vented and the WC is wet vented by the shower. The only thing you could drain into that shower vent (which would make the shower wet vented as well) would be bathroom fixtures (the lav), not anything from the laundry.

If you want to avoid the laundry drain crossing the shower vent, you could of course break open the slab and connect horizontally to one of the drains under the slab (after any wet venting, so after the hypothesized shower drain/WC drain joint).

Cheers, Wayne

Haven’t forgotten about you - been taking care of a sick grandpa this weekend and wasn’t able to do any framing/plumbing but hopeful tomorrow will work out.

Was able to check some of the pipes below slab and will draw them up tonight.

Thanks again!