DWV and Water supply renovation advice needed

[palych]

Hi everybody.

I have read this forum and will appreciate any suggestions and advice on DWV design and water supply pipe sizing design done by myself.
We have a 1.5 story Cape Code in NJ built in 1941 with one full bathroom on the first floor.
Current DWV system is cast iron:

I intend to do renovations in two steps:
1. remodel existing bathroom on the first floor (floor plan is 6'x6'). I keep cast iron for undeground line to the street:

2. add a second floor with additional bathrooms in a year or so (floor plans is 8'x8' and 4'x8'):

New Water Supply system design:

Also, I am thinking of installing tankless back-to-wall toilets.

I appreciate any suggestions and advice.

 

[palych]

Hi everybody,

Does anybody have any suggestions? Is my design too bad? Or there is nothing to correct?

Thank you

 

[Sponsor]

 

[Jeff H Young]

looks ok Id do it with vents if possible instead of aav but nothing stands out as not to code

 

[Reach4]

You might read https://terrylove.com/forums/index.php?threads/dwv-rough-in-question.91625/ which says the AAVs need to be signed off on, and we don't know how routine that is.

I don't know what NJ NSPC code says about wet venting a tub downstream of a WC. http://epubs.iapmo.org/NSPC/NJ2018/

 

[Jeff H Young]

I dont know NJ code either but just wouldnt put an aav when regular vent so easy.
Wet venting tub like that looks questionable too that might be real easy to vent off the stack or nearby wall

 

[palych]

Thank you both for your suggestions. I will update my design.
I have few more questions:
1. I am going to use PEX B with crimp fittings. Should I upsize my system or current diameters OK?
2. I am going to install Manifolds with 4 ports only - each port for group like bathrooms, laundry group, kitchen group. Should I upsize lines from Manifolds to 5/8" or keep it 1/2"? Is it OK or should I use Manifolds with ports for every fixture?
3. I am going to make recirculation dedicated line from Hot Water Manifold back to Water Heater. I did not find information on that. Is it OK?

Please advise.

Thank you