New Master Bedroom and Bathroom Addition

[Rayayork]

Hello, first time poster, long time reader looking for some help. I am installing a master bath in my new addition and have questions about flow and venting. There is a 40" crawlspace under the addition and the main sewer line out runs through this crawlspace. I have installed a 3" vertical vent from the crawlspace up through the roof of the addition to vent the bathroom fixtures. I am planning on a 3" sewer line under the bedroom to catch the shower, toilet and vanity. I plan on a 2" vertical vent for each location. The 2" vents will each rise from the crawlspace inside the 2x6 exterior wall and meet a horizontal 2" pipe via 2"x2" sanitary tee's approximately 4' from the floor. Each of the 4 drains will vent into the horizontal 2". The horizontal 2" will connect to a vertical 3" that rises through the roof with two 45degree bends before exiting the roof at 14" above the roof shingles. Will this pass inspection using IPC code in the state of Delaware? Any suggestions or alterations would be greatly appreciated. I have attached a hand drawing for a better visual. Thanks!

 

[MicEd69]

Sorry, but apparently you do not have a good understanding of venting. You do not vent the main sewer line at each fixture drain connection. The P-trap of each fixture is vented separately, or perhaps joined together if possible, and those vents are run to the vent stack. The one exception is the toilet which by IPC is vented by your 3" vent stack.

 

[Rayayork]

Sorry, but apparently you do not have a good understanding of venting. You do not vent the main sewer line at each fixture drain connection. The P-trap of each fixture is vented separately, or perhaps joined together if possible, and those vents are run to the vent stack. The one exception is the toilet which by IPC is vented by your 3" vent stack.

Hi MicEd69, the 3" horizontal in the crawlspace under the new addition isn't the main sewer line but it will dump into the main. The 3" vertical vent is just for the new master bath. Should it be smaller? So the vertical vent should not attach the the 3" horizontal? Thank you for your help.

 

[MicEd69]

Yes, I should have said the 3" branch. And no, you do not vent the 3" branch at each drain entry, just the 3" vent you show. Each P-trap must be vented in the trap arm. That is the line between the P-trap and where it meets the vertical line dropping into the 3" branch. And there are restrictions as to the length between the P-trap weir and the vent connection. The fitting for the vent in the drawing below is shown as a Sanitary tee on its back. IPC does not specifically disallow this. However, some inspectors may not allow this and rather want to use a combo fitting there.



And if you are close enough to the vertical drop to the 3" branch based on the maximum distances in the drawing above, your vent can be a continuation of the vertical drain line like this. The fitting in the drawing below must be a Sanitary tee.



There are other vent conditions/nuances that can come into play, as well as some local jurisdictions have other rules that may apply. And not to be mean, based on your first attempt for your layout, you may want to get a book on basic plumbing and get a better handle on plumbing design before you go much further.

 

[Twowaxhack]

Hello, first time poster, long time reader looking for some help. I am installing a master bath in my new addition and have questions about flow and venting. There is a 40" crawlspace under the addition and the main sewer line out runs through this crawlspace. I have installed a 3" vertical vent from the crawlspace up through the roof of the addition to vent the bathroom fixtures. I am planning on a 3" sewer line under the bedroom to catch the shower, toilet and vanity. I plan on a 2" vertical vent for each location. The 2" vents will each rise from the crawlspace inside the 2x6 exterior wall and meet a horizontal 2" pipe via 2"x2" sanitary tee's approximately 4' from the floor. Each of the 4 drains will vent into the horizontal 2". The horizontal 2" will connect to a vertical 3" that rises through the roof with two 45degree bends before exiting the roof at 14" above the roof shingles. Will this pass inspection using IPC code in the state of Delaware? Any suggestions or alterations would be greatly appreciated. I have attached a hand drawing for a better visual. Thanks!View attachment 42426

It would kinda work like you have it drawn if you were planning to use studor vents at the 2 fixtures. Toilet wouldn’t need one. Where are your p-traps ?

I’m not going to get into a code discussion and I personally wouldn’t pipe it that way.

Listen to MrEd and I’ll observe.

I’m going to suggest you hire a pro if you’ve never piped a bathroom before.

 

[user 32496]

The fitting for the vent in the drawing below is shown as a Sanitary tee on its back. IPC does not specifically disallow this. However, some inspectors may not allow this and rather want to use a combo fitting there.

Definity, use a combo or a wye rather than lay a sanitary tee on it's back in a drain application. It will save grief in the long run because not all inspectors allow a Sanitary tee to be laid on it's back in a drain application but it's okay on a dry vent.

The code (both IPC and UPC) say that the vent pipe opening shall not be below the weir of the trap.

IPC (2006) Section 906.2

906.2 Venting of fixture drains. The total fall in a fixture drain due to pipe slope shall not exceed the diameter of the fixture drain, nor shall the vent connection to a fixture drain, except for water closets, be below the weir of the trap.

UPC 905.5 The vent pipe opening from a soil or waste pipe, except for water closets and similar fixtures, shall not be below the weir of the trap.





A simple way to think about this is the "Eye see You" rule...

I need to see you, Plumbing Traps and Vents​

Wenatchee Home Inspections​

the trap has to see the vent



In your original drawing, you don't show the traps, but your vent openings are well below where the trap and the trap weir would have to be. Even though you have multiple vents in your branch line, your traps would be considered to have no vent.




The red below is how it should be hooked up. You are correct in using the Wye with the 45 degree elbow where the drain connects to the 3" branch. I was trying to label the connection from the trap arm to the drain and vent as a sanitary tee but my drawing app was not cooperating with me.

 

[MicEd69]

Here's some basic corrections to your original sketch. I hope this makes sense to you.

 

[user 32496]

Here's some basic corrections to your original sketch. I hope this makes sense to you.

View attachment 42467

I agree with @MicEd69. The drawing makes perfect sense to me. This is the plan I would go with, however, if you are getting it inspected, you could run it by the planning department to see what they think before doing the plumbing. If you aren't getting it inspected, then I'd just go with this plan.

The sink trap is likely 1 1/2" so the 6' max trap arm length is applicable with a 3" minimum trap arm length. This of course depends on a 1/4" per foot downward slope of the trap arm. The general statement of, "The vent pipe opening shall not be below the weir of the trap" over-rides any and all charts.

Also, IPC, generally, has no length specified between the toilet and a vent but it is possible Delaware has added amendments to the IPC code therefore the OP should google the plumbing codes for his area to see if there are amendments to IPC. I am also in an IPC code area but I installed a vent near my toilet just for my own piece-of-mind.





Note: Toilets are the exception to the general rule: "The vent pipe opening shall not be below the weir of the trap" because toilets depend on a syphon starting in order to work. After the flush, a toilet slowly refills the built in trap.

 

[Rayayork]

Thank you all very much!

 

[Rayayork]

I have drawn up what I hope is reasonably accurate. I added a washer as it will be in the bathroom as well. I have a 3" stub rising above the shingles 13". Is it okay for the vertical 2" to be converted to 3" before going through the roof? Thoughts? Thanks again for all of your help. By the way, I called a Pro yesterday to get an estimate. He scheduled today at 11AM and didn't show. I texted him and he said let's do1PM. It is now 4:45PM and no show and no text.

 

[user 32496]

I’m assuming you’re 3” through the roof is an existing roof penetration? Going from 2” to 3” is not a problem but do you still have a 3” main stack somewhere?

 

[Rayayork]

I added a 3" stub through the roof of the new addition while they were roofing and was hoping to reduce to 2" down to the first floor and tie into the horizontal 2" vent pipe. Everything in the drawing is new and will be separate from the main house with the exception of the tie into the 3" main sewer in the crawlspace. The main house does have a 3" main stack.

 

[MicEd69]

I'm not sure why you ran a 4" line from the toilet and then reduced it to 3", but you cannot do that. You cannot reduce the size of a drain line in the direction of flow. But you can make the toilet drain 3" all the way and that would be just fine.

You are venting the toilet with a 2" line just downstream where it enters the branch, which is fine. But if you increase vanity line to 2", if you are under IPC with no local restrictions, that would serve as a wet vent for the toilet. And with the shower and the washing machine, in reality those lines would properly vent the toilet as well, I'm just not surer they would be per code.

The 2" increasing up to a 3" vent protrusion is not a problem, as long as you do have the 3" vent in another location.

 

[Twowaxhack]

A 4x3 90 under the toilet is fine but like was said, you can’t run 4” then reduce to 3 in the drainage system.

 

[Rayayork]

In my last drawing it appears all fixtures are on one wall but they are actually on 3 walls in the bathroom. Am I allowed to use a 90 in the corners of the 2" horizontal vent line? There is a floor above and not an attic. I attached a rough sketch. Thank you.

 

[havasu]

It is harder and harder to have the professionals comment on rough sketches done in pen, with no distances for them to visualize how many feet away the venting is from the source. Does that end piece connect to the roof, or tied to upstairs plumbing?

 

[Rayayork]

Sorry for the elementary drawing and thanks for your patience. The master bed and bath is a 2 story addition. The bed and bath are on the first floor with a crawlspace underneath. Above the bed/bath is a storage room that will be finished in the future with no bathroom or plumbing required. The bathroom dimensions are 12'x12'. The horizontal 2" vent will be tied into a new 2" vertical vent that converts to 3" before exiting the roof and capped over the vanity and the washer if allowed. The 2" horizontal vent would tie into a new 2" vertical vent about 8' into the walk in closet. I am confused on if I can use 90 degree bends at the shower and the vanity to stay inside the walls. Thanks much.

 

[MicEd69]

As long as the vents are dry vents, that means the vent piping is at least 6" above all the flood levels of the fixtures served, the only restriction is that the piping be sloped at least 1/4" per foot back towards the drain piping. The only thing that is in that dry vent piping is air and a little rainwater and perhaps condensation. But things do happen.

So, when you say the lines will be "capped" at the vanity and the washing machine, you don't want to do that exactly. You should provide a cleanout at those locations just in case you need to snake those out due to a vent problem in the future.

 

[Rayayork]

Thanks. What type of 90 degree bends can I use on the horizontal 2"?

 

[MicEd69]

You can use any 90s you want. Long radius ones are easier to snake, but really that is not a big deal for a vent.