Author Topic: Little cabin plumbing movie  (Read 7313 times)

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Pa_Kettle

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Little cabin plumbing movie
« on: October 09, 2007, 03:00:37 PM »
Now that we've started to work on the inside of the cabin, I really need to nail down the plumbing and electrical details.

I've posted a short video of how I think we should do the plumbing.  I (roughly) modeled the cabin in Blender (http://www.blender.org/) and then did an animation with it.

Basically we have a stand up shower, toilet and sink in the bathroom and a wash tub on the other side of the "wet wall" in the kitchen.  I've colored the shower auxillary vent red.  I think I can get by with no auxillary vents for the sink and wash tub.  The main vent stack goes up the wet wall, across the bottom of the loft and out the roof.



Anyone have a insight? Criticism?

I've got a 3" (or 4"?) main drain/vent pipe.  Can I drop down to a smaller pipe for the top of that main vent?

I've kept the trap for the shower up inside the floor joists to help it resist freezing.  That drain goes horizontal for a bit and then dives down and turns to hit the drain/vent stack.  Any gotchas with that plan?

Does anyone have pictures or drawings of how they did it in a similar cabin/setup?


Thanks!
PK

glenn-k

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Re: Little cabin plumbing movie
« Reply #1 on: October 09, 2007, 06:06:20 PM »
Total vent area is supposed to equal the size of pipe going out to the septic tank.  If you have enough small ones exiting the roof to equal the "pipe size you can get by with them - Toilet is 2" vent min. as I recall.  4" should not be necessary for this small cabin.

You have wet/vented  / no vented fixtures - which while they will probably work, probably won't be allowed.  Wet vents are allowed in some instances but there are so many problems with inspector interpretation of those instances, I try to never do it.  Every fixture needs a vent to keep from sucking the trap dry and letting sewer gas into the house.  The shower appears to be vented properly.  Do similar with the others.  Make the water go down -- the air go up.

Water cannot flow down the toilet vent either as this wet vents it. You could wye into the waste line before the toilet off the upper 1/3 of the pipe -- run it -maybe 2 inch back to collect the sink/washtub water - waste water can flow over waste water - then the toilet vent can go up the 3 inch and all other vents can tie into the 3 inch toilet vent. In this way all water will go down - all air up with no water flowing down a vent.
« Last Edit: October 09, 2007, 06:10:23 PM by glenn-k »

StinkerBell

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Re: Little cabin plumbing movie
« Reply #2 on: October 09, 2007, 06:07:24 PM »
That was pretty neat to watch. :D

Pa_Kettle

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Re: Little cabin plumbing movie
« Reply #3 on: October 10, 2007, 05:53:37 AM »
Quote
Total vent area is supposed to equal the size of pipe going out to the septic tank.  If you have enough small ones exiting the roof to equal the "pipe size you can get by with them - Toilet is 2" vent min. as I recall.  4" should not be necessary for this small cabin.
I think I'm going to go with 3".  We don't have codes out here so I'm on my own.

Quote
You have wet/vented  / no vented fixtures - which while they will probably work, probably won't be allowed.  Wet vents are allowed in some instances but there are so many problems with inspector interpretation of those instances, I try to never do it.  Every fixture needs a vent to keep from sucking the trap dry and letting sewer gas into the house.  The shower appears to be vented properly.  Do similar with the others.  Make the water go down -- the air go up.
From what I can understand (plumbing info on new small installations is scare), if the drains are within a certain distance of the main vert. vent, you don't need aux. venting.  Both of these drains are less than 3 ft away from the main stack, but I'll add a vent if you think it'll perform better.

Quote
Water cannot flow down the toilet vent either as this wet vents it. You could wye into the waste line before the toilet off the upper 1/3 of the pipe -- run it -maybe 2 inch back to collect the sink/washtub water - waste water can flow over waste water - then the toilet vent can go up the 3 inch and all other vents can tie into the 3 inch toilet vent. In this way all water will go down - all air up with no water flowing down a vent.
Ok, you have confused me here.  The toilet runs to the main stack, so every drain above it makes it a wet vent, but every diagram I've seen does the toilet this way and they don't label it as a wet vent.

In the attached drawing you can see they do consider the vent between the basin and the shower wet, but not the vent between the shower and the toilet.

Thanks for the info!  I hope we can get a few more people chiming in.  Then I'll build by popular vote.  ;D

PK

Pa_Kettle

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Re: Little cabin plumbing movie
« Reply #4 on: October 10, 2007, 05:56:25 AM »
Quote
That was pretty neat to watch. :D
Thanks. :)  When I get the plumbing completely nailed down, I'll do a longer fly by of just that area of the house.

PK

Offline glenn kangiser

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Re: Little cabin plumbing movie
« Reply #5 on: October 10, 2007, 07:21:04 AM »
In my opinion, PK, I don't see what all the wet vent fuss is about and as I read it - like you, I don't see any problem with venting the way you show.

I was taught that way -- have had issues with inspectors over the wet vent thing and they got into an --can't consider or decide about it without an act of congress stance, so I have just always avoided the issue.  I also read the part about the certain wet vents being allowable.  They may have lightened up on it over the years - I was doing it in about 1984 - just kept the same procedures for current occasional jobs as it always passes.
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Offline MountainDon

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Re: Little cabin plumbing movie
« Reply #6 on: October 10, 2007, 10:05:55 AM »
Around here the inspectors get upset and will red tag if you place a drain into a stack pipe above a vent line connection. They make you run a vent line up above any connecting drains and then tie into the stack.  If it's a 2 story building you find vent pipes from the lower floors running up thru the walls to a point above any upper floor drain connections, or up through the roof separately.



Now with that said, I personally think that the only time you might encounter a problem is if the sink drain above the tub or toilet drains, is draining a load of water at the same time as the tub or toilet. You might get some gurgling or whatever.   :-/
« Last Edit: October 10, 2007, 10:24:09 AM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

Offline glenn kangiser

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Re: Little cabin plumbing movie
« Reply #7 on: October 10, 2007, 10:27:34 AM »
That's the same experience I've had around here, Don.  Isn't that second floor toilet (lower toilet on the right) in your picture unvented or wet vented if the sink vent is close enough?
« Last Edit: October 10, 2007, 10:29:13 AM by glenn-k »
"Always work from the general to the specific." J. Raabe

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Offline glenn kangiser

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Re: Little cabin plumbing movie
« Reply #8 on: October 10, 2007, 10:33:57 AM »
Actually if I was doing it, I would run that toilet vent up and across to join the sink vent or near it.  If I have a question about something that is going to be inspected but I know a way that will pass without causing me too much trouble, I just go ahead and do it.  Re-inspections hold up jobs and sometimes cost money.
« Last Edit: October 10, 2007, 10:36:15 AM by glenn-k »
"Always work from the general to the specific." J. Raabe

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Please put your area in your sig line so we can assist with location specific answers.

Offline MountainDon

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Re: Little cabin plumbing movie
« Reply #9 on: October 10, 2007, 12:14:55 PM »
Good catch. I was wondering about that toilet myself,  :-/ but I couldn't find a better picture.

I'd likely run a vent like you indicated. It's better to do something like that and be sure rather than have to go through a re-inspection and have other work held up.  :)  Very little extra time or expense needed.

Good thing my RV didn't need to be inspected.  ;D  Where it's parked I run the grey dump hose into a bucket buried in the ground. Holes drilled in the bottom and have a screen across the mouth where the hose dumps in. Even the small amount of food particles, etc. that get caught in the screen makes a bad smell. Doesn't last long as it dries out, but each time I pull the dump valve it stinks.
« Last Edit: October 10, 2007, 12:20:02 PM by MountainDon »
Just because something has been done and has not failed, doesn’t mean it is good design.

 

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