New Construction Basement Plumbing Advice

[KristofMI]

I'm building my house in Michigan. They use IPC code. I need to rough in basement bathroom before they pour the slab. Do this drawing and connections looks right to you? On the other side of the wall we will have a washer and dryer.

It's my first time ever doing and designing rough plumbing so please go easy one me

 

[Tuttles Revenge]

Generally I think your schematic looks good. I couldn't verify whether a toilet vent can accept the discharge of the clothes washer as a wet, but I didn't see it excluded. The lavatory sink definitely can. The sump basin requires its own vent to allow for displacement of air as its being filled up.

 

[Sponsor]

 

[KristofMI]

Generally I think your schematic looks good. I couldn't verify whether a toilet vent can accept the discharge of the clothes washer as a wet, but I didn't see it excluded. The lavatory sink definitely can. The sump basin requires its own vent to allow for displacement of air as its being filled up.

I can definitely move it to vanity vent. And yes about the basin vent. I just simply forgot to add it. Also it's just a sketch not to dimension

 

[KristofMI]

 

[KristofMI]

Will the above work? Also IPC requires 1.5" minimum for vents. Can I do all vents 2" ? Is it going to cause problems down the road? Like finding connectors/fittings? Or connecting sinks.

 

[Tuttles Revenge]

I almost didn't see the difference. The laundry and toilet now have their own dedicated vents. That works. I don't know if the original drawing wasn't just fine, I just don't have the first hand experience with the IPC to know out of hand if laundry can't wet vent, I just think it can't.

But each fixture individually vented is fine.

To calculate the vent load you need to use the venting sizing chart. Each fixture has its own DFU / Drainage Fixture Unit value. Every sized pipe has the capacity to accept the DFU of waste and venting.

I don't know exactly how IPC calculates vent load but the resource that I've found : https://up.codes/viewer/michigan/mi-residential-code-2015/chapter/31/vents#31

 

[KristofMI]

I almost didn't see the difference. The laundry and toilet now have their own dedicated vents. That works. I don't know if the original drawing wasn't just fine, I just don't have the first hand experience with the IPC to know out of hand if laundry can't wet vent, I just think it can't.

But each fixture individually vented is fine.

To calculate the vent load you need to use the venting sizing chart. Each fixture has its own DFU / Drainage Fixture Unit value. Every sized pipe has the capacity to accept the DFU of waste and venting.

I don't know exactly how IPC calculates vent load but the resource that I've found : https://up.codes/viewer/michigan/mi-residential-code-2015/chapter/31/vents#31

I have been told in IPC your are not allowed to use toilet vent as a wet vent.

 

[John Gayewski]

Will the above work? Also IPC requires 1.5" minimum for vents. Can I do all vents 2" ? Is it going to cause problems down the road? Like finding connectors/fittings? Or connecting sinks.

Don't use that double wye for the washer and shower drains. Use individual wyes. That fitting would have to lay perfectly flat and we generally just use those vertically.

 

[Tuttles Revenge]

Don't use that double wye for the washer and shower drains. Use individual wyes. That fitting would have to lay perfectly flat and we generally just use those vertically.

Good catch. I didn't see that change from original. Our jurisdiction has an exception for a double WYE but only if its installed with street 45's to correct the grade recognizing that the 2" of flat in the fitting is negligable... However.. not all jurisdictions recognize that and would be illegal to install.

 

[KristofMI]

I want to save me some time digging. Can I put washer standpipe on sink drain?

 

[Tuttles Revenge]

I want to save me some time digging. Can I put washer standpipe on sink drain?
View attachment 91985

Yes, because you show the clothes washer trap arm is vented, from that point downstream of the vent, it becomes a common drain.

 

[KristofMI]

Yes, because you show the clothes washer trap arm is vented, from that point downstream of the vent, it becomes a common drain.

Got it. Will same situation be allowed if the clothes washer wasn't vented like I showed?

 

[wwhitney]

Quick comment on IPC wet venting allowances:

What IPC calls wet venting is only for bathroom fixtures. But the IPC also allow any two fixtures to be "common vented". The vertical version is called "common venting at different levels." The only restriction is the upper fixture can't be a WC. The vertical "common vent" between the two fixtures is sized based on the DFU of the upper fixture--1-1/2" for 1 DFU, 2" for up to 4 DFU, 3" for up to 6 DFU.

Chapter 9 Vents: Vents, Michigan Plumbing Code 2018 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

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Cheers, Wayne

P.S. On the "flat" double wye, if the two side entries are perfectly level with each other, then the pitch on the side entries will be 71% of the barrel pitch. So with 2% barrel pitch, the side entries are too flat. If you increase the barrel pitch to 3%, then in theory there's no problem with the side entry pitch. But in practice it would be very difficult to get the two side entries perfectly level with each other, and if one entry is lower than the other, it would be too flat. Thus jurisdictions may have different approaches to allowing it or not. But whenever you have room for individual wyes, that is a better solution.