"Speedy Jim" wrote in message
...
davidmc wrote:

My problem is how i should vent an additional bathroom that i would
like to add to my 1930 house. It currently has only 1 bathroom, which
is on the 2nd floor. There is a 4" drainpipe and a 3" vent, both of
which extend from the basement to the 2nd floor (and the vent thru the
roof). It's impractical for me to add a new bathroom either near the
existing DWV lines, so i would have to convert a mud room in the corner
of the first floor house into the proposed bathroom. I can easily add
a drain from the mud room into the basement, but i don't know where i
can add a vent pipe. Adding a bathroom would be impractical if i have
to tear the house up to add new vent pipes.

Here are the options that i can think of so far:
1)Is it acceptable to have a vent pipe that extends upward @6" from the
trap, then back down into the basement to connect to the vent pipe
there? Or do i have to have the vent pipe travel upwards and over to
connect to the vent pipe above the highest trap in the house?

2) can i get away with a "cheater valve" which means i wouldn't have to
install new vent pipes?

3) do i need a separate vent pipe at all? if the waste line is 4",
might there always be air in the line to serve as a vent?

I live in Massachusetts, and i'm having a hard time interpreting the
state plumbing code. I don't plan on doing the work myself, but i
need to know if this is even feasible, and i want to know if i should
be suspicious of a plumber who proposes the most expensive solution.


In Mass., count on the approved solution being the most expensive.

I can't imagine that they would allow a mech vent to serve an entire
bath. Nor a vent which loops downward.

Take a deep breath and have a man-to-man with the town inspector.
He may alert you to other requirements you haven't even thought
of yet.

Jim

Jim makes a good point talking to the town inspector. As well as letting
you know what other requirements you need to be aware of, they will likely
give you options that they are willing to approve.

I find that being a homeowner and taxpayer, they are more that willing to
work with me. Contractors on the other hand are getting paid to do a job
and are supposed to know, so they are less helpful with them.

David