Basement Bath Vent

[Deats]

Hi,

Just want to say thank you for a great site. I often come here to do my research. I'm sure this question may have come up I did a search but could find anything. If this is the wrong location for this question or if it's been previously answered please let me know. This is my first post...

I'm trying to vent a basement bathroom and have a question regarding connection to my existing 1st floor bath vent. My question is can I connect a 2" vent pipe from the basement bath to a 1" 1/2 vent from the 1st floor bath? I'm aware of the code that it has to be 42" above the floor or 6" above highest fixture I'm just not sure if I can go from 2" from basement to existing 1" 1/2 that runs up to the attic which vents out 3" through the roof. The 1st floor bath vent is actually fairly easy to access and why it's my first choice. I attached a diagram to show what I'm trying to do and appreciate any advice the experts here could offer.

Thank you,
Deats

 

[Terry]

The 2" stays 2", but can also be larger.
Not smaller.

 

[Sponsor]

 

[Deats]

The 2" stays 2", but can also be larger.
Not smaller.

Thank you. I'll have to take the 2" to the attic then.