Tear apart my plan

[mechmess]

I've got an offset vent stack where in the existing bathroom the toilet sits directly on top of it and a Santee transitions over to the vent.

Please tear apart my plan to move the toilet by ~4' and re-route the whole bathroom.

 

[Nukedaddy]

Looks like way too many drainage fixture units trying to wet vent off lavatory. Not only looks like too many, it is! Is there no way to connect the waste stack (in red) to the existing 3” roof vent? That would allow the toilet to connect within 5’ of the vent connection. Then a common vent between the tub and shower connected above FLR for the lav would complete a conventional vent system.

 

[mechmess]

Looks like way too many drainage fixture units trying to wet vent off lavatory. Not only looks like too many, it is! Is there no way to connect the waste stack (in red) to the existing 3” roof vent? That would allow the toilet to connect within 5’ of the vent connection. Then a common vent between the tub and shower connected above FLR for the lav would complete a conventional vent system.

Thank you so much for reviewing!!

My preference would be to do as you suggest and provide a connection between the red stack and the existing vent. However, I don’t know if I have room in the joist (see attached). My idea was to try and use a low heel 90 (3x2x3) and either a street 45 or street 90 at the top of it to jog over to the existing 3”vent.... it’s really got me scratching my head!!

I may have to pay someone to come give it their *professional* two cents....

Thanks again!!

 

[Pat the Plumber CIL]

First shower drain has to be 2" min , you show a 2x2x1.5 wye at shower .Need a 2x2x2 wye and 2 " p-trap . Each trap should be vented individually for best results . Most people do know understand importance of proper venting . You can wet vent one drain with another but gets complicated to use a common vent for all . A vents main purpose is to prevent P-trap from siphoning . Also a properly vented sewer line is less likely to get sewer flies. Drain piping made out of metal will not last long if not properly vented . Vent should connect after fixture trap but before common drain .
In your picture sewer pipe does not look like schedule 40 DWV fittings . looks more like thinwall sewer pipe ( SDR 35) . Good luck trying to get it all together in that amount of space

 

[frodo]

what size is the floor joists?
that is going to determine what can or can not be done

lay these fittings out and measure bottom of the trap to the center line of the 90
this will set the drain elevation


do not use 1 1/2'' on the tub. use 2''

 

[mechmess]

what size is the floor joists?
that is going to determine what can or can not be done

lay these fittings out and measure bottom of the trap to the center line of the 90
this will set the drain elevation


do not use 1 1/2'' on the tub. use 2''

2x10 Joists - your comment to measure was great - I stupidly hadn’t even thought about the traps eating up all the available space... I think those measurements are going to shake things up quite a bit.

Thank you all!

 

[frodo]

Couple of things you have to know when you are horizontal venting.
one is if the vent is a dry vent, [dry means nothing else is draining into it] then the horizontal take off of the vent from the horizontal drain line SHALL be rolled so that the invert is above the flow line .
WOW..WHAT THE HELL>> LOL
here is a picture

2 vents below, one is a rolled vent.
the other is a wet vent. the wet vent does not have to be rolled
the dry vent does.

ALSO. the vent take off HAS to be down stream of the fixture. NOT UPSTREAM
in your drawing you have a couple vents that are upstream. SEE another funky drawing

 

[mechmess]

Couple of things you have to know when you are horizontal venting.
one is if the vent is a dry vent, [dry means nothing else is draining into it] then the horizontal take off of the vent from the horizontal drain line SHALL be rolled so that the invert is above the flow line .
WOW..WHAT THE HELL>> LOL
here is a picture

2 vents below, one is a rolled vent.
the other is a wet vent. the wet vent does not have to be rolled
the dry vent does.

ALSO. the vent take off HAS to be down stream of the fixture. NOT UPSTREAM
in your drawing you have a couple vents that are upstream. SEE another funky drawing
View attachment 24200
View attachment 24198

View attachment 24199

VERY helpful.

One thing I don’t quite get though - when you mention that I have some vents that aren’t downstream, aren’t all of my vents downstream/washed by the lav, therefore making them wet vents? I’m confused as to how I could attach the other fixtures to the horizontal wet vent line in a different way...

The rolled wye diagram is super helpful- I couldn’t for the life of me figure out how that was supposed to be done, given that everything I’ve read has indicated that the vent has to be at 45 degrees minimum to the vertical unless it’s above the flood level.

 

[frodo]

 

[Nukedaddy]

I just had a thought that you may not have considered. There must be at least 1 full sized vent for the system. Your sketch and the others are good for figuring out what might work, but if the 3” out the roof is the only “main” vent, most if not all codes will not allow you to reduce the vent size to 2” from the top of the 3” waste stack to the bottom of the 3” vent stack. If there is another 3 or 4” vent through roof in the house, this rule may not apply.

 

[mechmess]

View attachment 24211View attachment 24212

Thanks! This clears it up for me.

 

[mechmess]

I just had a thought that you may not have considered. There must be at least 1 full sized vent for the system. Your sketch and the others are good for figuring out what might work, but if the 3” out the roof is the only “main” vent, most if not all codes will not allow you to reduce the vent size to 2” from the top of the 3” waste stack to the bottom of the 3” vent stack. If there is another 3 or 4” vent through roof in the house, this rule may not apply.

I had not considered that... that really sucks as the only way I can can think of to provide a code compliment continuous vent would be a 45 degree offset in a soffit on the ceiling of the lower level....

There is another vent for the house, but it’s only 2” :/