Advice on new plumbing and vent layout for addition

[Wjy]

Hello all,
I used the resources on this site to help me come up with the design and layout of the plumbing and vent systems for the addition in my house that will be built in about a month. I will be doing the plumbing work myself and want to check with the experts to ensure that my design will work properly before I proceed. The waste line will be under a crawl space and will have 1/4” per foot slope until it connects with the 3” wet vent in the main house. The vents for the vanity and shower will connect with the vent for the washer in the attic, and from there the 1.5” pvc vent will go out to the roof. The vent pipes will be sloped. Please let me know if you see any issues. Any suggestions/recommendations would be greatly appreciated. Thanks in advance.

 

[Terry]

I would find a way to use the lav run with 2" through the roof to wet vent both the toilet and the shower.
I would bring the washer downstream of that and vent that with 1.5" for it's 2" standpipe. That could tie back into the 2" vent for the bathroom.
I don't know that what you call a 3" wet vent is going to help you. You can wet vent the bathroom group if the washer isn't part of it.

 

[Sponsor]

 

[Wjy]

Thanks for the quick response and the tips, Terry. It will save me some time and effort not having to vent each fixture separately. Please look at attached picture and let me know if I understood you correctly. If it’s correct then Would I be able to make the washer vent a 2” and have the Lav vent connect with it at the washer and then go up thru the roof ? I am asking because the Lav is located on an outside wall and would require bends in the attic to go up thru roof so it’s away from roof edge. The washer is closer to the center of the addition and I would be able to go straight up. Thanks again.

 

[Wjy]

Corrected drawing. Previous drawing was not downstream of bathroom group. My question is, If I change to 2” to vent washer, can I tie bathroom group vent to this and then up thru roof near washer? Thank you.