dwv in new log home, UPC

**69gtocv** · 06-06-2010, 06:35 PM

Hi, Trying to DIY my DWV in our log home we are building. The house is in Montana which is under UPC codes. My county does not require inspections but I would like to design this system as if it would have to pass one. My main issue is that we have a master bath in the second floor loft of the house and as you can see from the picture, there is no way to do a wet wall for supply/vent on this wall due to the enormous stud pack. What I've decided to do is build out a soffit wall between where the vanity will go and that existing stud wall. The soffit wall will have to be taller than the countertop to allow me to run the vent horizontal once it gets 6 inches above the sink. Once passed the end of the counter/vanity it can turn vertical to where I can run it out the roof. I have no way of venting the toilet besides wet venting it via one of the lav sinks. I believe this is ok, yes? The jacuzzi tub to the right will also be vented by the lav on the right. If I get the ok on this level, I can then post what I'm thinking for the main level bathroom.

Thanks, Jeff

**Terry** · 06-06-2010, 07:13 PM

I would wet vent the toilet with the lavs using 2" the entire way for the vent.
Or you could bring up a second vent for the tub or toilet too.
You will need either a single 3" vent or if you have fixtures other places, you can use two 2" vents and one 1.5"
Toilets need 2" minimum under UPC

**ipsinc** · 06-07-2010, 04:53 AM

upsize your vent to 3"--DO NOT USE WYES--use sanitary tees for the other fixture tie ins or you will create airflow issues ( and violate the codes)--also you do not have to extend the furr out above the flood level rim of the sink , you can vent this fixture, per code without doing so--run the vent the same as you would above the sink, jsut use drainage fitting instead of vent fittings--also---code compliancy while the best way to go, the IPC and UPC differ greatly on this exact subject and the IPC is getting ready to basically over throw the UPC--what I am saying is functionality and code compliancy are two different things--the ipc gives far greater lattitude on venting of fixtures--I can and will answer any questions as to the UPC mandates, as that is what I am most familiar with---so--3x3 san tee for the toilet drain, stack a 3x2 for the tub then on top us e a 3x11/2"--this is not code allowed per upc but will work fine and is ok by the ICC----to comply with UPC, youd have to either wet vent only the lav and run a separate drain for the tub

hj · 06-07-2010, 06:36 AM

quote: "--DO NOT USE WYES--use sanitary tees for the other fixture tie ins or you will create airflow issues ( and violate the codes)--

If that is an example of your "expertise", then I might question the rest of the advice. There is NO, repeat absolutely NO, prohibition as far as using "Y"s, combos, or ANY other fittings in the vent system. The IPC is NOT likely to usurp the UPC, at least as long as there are "good" plumbers using the UPC. When they start getting lazy, then they may vote to use the IPC.

In this case, I might use a single riser between the lavatories, with a "back to back fixture fitting" and a single vent. With a log house the more important feature is to provide an expansion/contraction device in the risers to accomodate the "shrinkage" as the wood ages. (Doors and windows can have the same problem.)

**jimbo** · 06-07-2010, 06:49 AM

If this is a true log home, are you and your plumbing contractor familiar with the necessary construction techniques for the piping, to accomodate for the settling of the logs? I watched the construction of a log home on a tv series some time back, and settling is signiicant and there are special construction techniques to deal with it.

**69gtocv** · 06-07-2010, 09:09 AM

Originally Posted by Terry

I would wet vent the toilet with the lavs using 2" the entire way for the vent.
Or you could bring up a second vent for the toilet too.
You will need either a single 3" vent or if you have fixtures other places, you can use two 2" vents and one 1.5"
Toilets need 2" minimum under UPC

Terry, I was just going to reply to your post from last night when I see you changed it to this this morning. Your original answer said I should wet vent the toilet with the left lav and the tub with the right. I thought that's what I was doing in my pictures. Then you said you didn't like the tub draining by both lavs and the toilet. You went on to say to do wyes into the 3" drain line. I was hoping for a picture, but now you've posted this. I was planning on 2" venting for this configuration. 1 1/2" drains from the lavs, 2" drain from the tub and 3x3 for the toilet (no reason to do a 4 to a 3 on the toilet?). Now this picture you just posted has me confused. I'm not able to run a separate vent from the toilet through the stud pack behind as I'd be compromising my king studs for the window above it. I can't run the vent from the toilet horizontal until it's 6" above rim height. I was trying to avoid having to build a second soffit wall behind the toilet, but if I did, I could then tie the vent from the toilet into the vertical vent going up alongside the vanity, but it would then push the toilet further out in the room.

Jeff

**69gtocv** · 06-07-2010, 09:24 AM

Originally Posted by hj

quote:
In this case, I might use a single riser between the lavatories, with a "back to back fixture fitting" and a single vent. With a log house the more important feature is to provide an expansion/contraction device in the risers to accomodate the "shrinkage" as the wood ages. (Doors and windows can have the same problem.)

HJ, Are you saying use a single vent going up from between the two lavs, then turning horizontal to the end of the lav, then vertical from there? I guess I thought because I was trying to wet vent the tub with one and the toilet with the other, I should keep them separate, then combine then before going up. What's the advantage in your suggestion? I still have to go to the left of the lav before going through the roof as I have windows and a log ridgebeam directly over the center. I am very much a rookie in this and definitely open to all suggestions. Oh and yes, I'm very familiar with the shrinkage issues, but for this floor, it's all stick built, the main floor below which I haven't touched on is where that issue will come up.

**69gtocv** · 06-07-2010, 10:14 AM

Here is my main floor bath configuration. I will have to use expansion joints in the settling gaps. Is there a preferred make of those and what exactly are they called? Also, what wyes etc am I looking for in this bathroom. I have to run to buy some supplies before heading over to Montana in a couple of hours. Apparently there is much use of ABS in this small town (they prefer PVC) where I'm buidling it, but I already have quite a few ABS fittings, so I'm going to have to stock up here before heading there.

**jadnashua** · 06-07-2010, 10:35 AM

Keep in mind that once a line becomes a drain, it is NOT available as a vent on another floor. The vent from the first floor must go up 6" above the flood plane of the upstairs bath to connect into that vent line. that's typically about 42" above the floor of the second story bath.

**69gtocv** · 06-07-2010, 11:05 AM

Originally Posted by jadnashua

Keep in mind that once a line becomes a drain, it is NOT available as a vent on another floor. The vent from the first floor must go up 6" above the flood plane of the upstairs bath to connect into that vent line. that's typically about 42" above the floor of the second story bath.

Jim, thanks. The vent coming from the main floor bathroom will run independent and exit the roof all its own. It will not connect into the vent going through the roof on my first post of the upstairs bath. I should have made that more clear on my drawings. Also I couldn't accurately show it on this drawing, but the main drain coming down from upstairs will wye into the drain from this main bathroom downstream a bit before that final drain connects to the 4" pipe heading out to my septic tank.

**worsnup** · 06-07-2010, 12:25 PM

Phoenix whent to ipc last year

hj · 06-07-2010, 12:35 PM

Only residential. Commercial is still UPC.
Those pictures with branch lines to the lavatories is the way I would do it. You can make the left one a lot shorter since that seems to be the direction you have to "jog" the vent to.

**69gtocv** · 06-07-2010, 08:47 PM

Originally Posted by hj

Only residential. Commercial is still UPC.
Those pictures with branch lines to the lavatories is the way I would do it. You can make the left one a lot shorter since that seems to be the direction you have to "jog" the vent to.

Are you referring to Terry's picture in post #2? I'm not sure which picture to look at. Can you draw a picture showing the shorter branch?

hj · 06-08-2010, 06:18 AM

Move the vertical riser closer to the left hand sink. That way, the left one will have a short branch and the right sink a longer one. Since you apparently are offsetting to the left with your vent arm, this will minimize its length slightly.

When I found out that Phoenix went IPC, I called downtown to verify it, and then asked the lady, "I guess that means almost anything is legal now?" and she answered, "Yes".

**69gtocv** · 06-08-2010, 10:31 AM

Originally Posted by hj

Move the vertical riser closer to the left hand sink. That way, the left one will have a short branch and the right sink a longer one. Since you apparently are offsetting to the left with your vent arm, this will minimize its length slightly.
.

Ok, so use the example of what Terry posted in #2 but move the vertical riser closer to the left. Got it. For my clarification, the cross in the middle in his picture is the "back to back fixture fitting", correct? And I should increase the lav drains to 2" after the tail pieces or not until after the P traps or keep at 1 1/2"? Once I turn vertical to go up out the roof, increase that vent to 3"? But is this setup still going to accomplish what I need.. to wet vent the toilet AND tub? I have no place to bring up a vent from the tub without going horizontal first (not allowed) as there is a window right behind it as you can see in the picture in post #1. Maybe I need to just wet vent the tub with the right lav by inself, run a separate drain line then to tie into the 3" watercloset line downstream of where the left lav will intersect? Where I intersect the 3" line, I can use a 3x2 wye laid horizontal, correct? Do they make a closet bend with a 2" side inlet so that I could keep that line coming from the lav closer to the wall? Thanks for helping me with this. Oh, and does the main floor bath configuration I posted in #8 look good?