Wet vent question

[grover]

Can I drain a washing machine and lavatory through a 3" line into a 3" line (toilet drain) and use the washing machine and lav drain as a wet vent for the toilet? Would a 2 1/2 inch wet vent work. I'm not even sure they make 2 1/2 but I think I remember seeing it in a book somewhere.

Associated question is can I put a 3 1/2 in hole in a 2 x 10 if I reinforce the 2 x 10 some way. I know the hole will be larger than the 1/3rd rule, that is why I ask. The hole will be within a foot of the support wall. If I can reinforce the 2 x, how best is that done?

 

[grover]

I'll do some more research.

 

[Sponsor]

 

[Krow]

Can I drain a washing machine and lavatory through a 3" line into a 3" line (toilet drain) and use the washing machine and lav drain as a wet vent for the toilet? Would a 2 1/2 inch wet vent work. I'm not even sure they make 2 1/2 but I think I remember seeing it in a book somewhere.

2" drain into a 3" drain is sufficient, 3" drain into a 3" drain is better IMO. They do not make 2 1/2" waste pipes, however they did make a 2 1/2" copper pressure pipe (not a very common size).

Associated question is can I put a 3 1/2 in hole in a 2 x 10 if I reinforce the 2 x 10 some way. I know the hole will be larger than the 1/3rd rule, that is why I ask. The hole will be within a foot of the support wall. If I can reinforce the 2 x, how best is that done?

You answered your own question referring to the 1/3rd rule. Just to clarify, its not recommended no matter how you try to reinforce it.