I'll be doing plumbing on a new house and have a question. I see the houses
around here where the plumbers run the main vent and an average of 3
secondary vents right up through the roof wherever they enter the attic. On
one particular house I saw yesterday they ran a secondary vent up an
exterior wall which comes out the front of the house roof near the corner
which makes it about 2 feet or so away from the gutter. This looks
horrible. In fact any vent on the front of the house looks bad.

Can I elbow (45 and 45) my main in the attic so that it exits out the back
side of the houses roof? Can I also elbow any secondary vents toward the
back too? In addition could I tie all secondary vents into the main vent in
the attic?

I will be asking the inspector down the line but we are still waiting for
the house plans to be drawn up so I thought I would see what is done around
the country first.

TIA

Gary

That sounds pretty ugly. You'll want to talk to the inspector for sure,
cause nobody around here is going to come to any kind of consensus.

But, the usual idea is to try and get most of the plumbing on one side
of the house, so many of the pipes can be run basically in a single
wall, usually the back of the house. This makes the venting easy.

Yes, you can put in bends in the venting, and yes it should be sloped.
I don't THINK 45 is necessary, just the usual slope so that rain or
whatever else gets in there can drain back down. And you have to be
careful that nothing drains in above the point where the vents come
together, of course, which isn't a problem in an attic. The rules are
likely different for the 3'' main vent than the smaller secondary
vents.

That said, our house venting runs all over creation, but we manage to
get away with just a single 3'' vent in the back, and a few of those
little under-sink venting things with the rubber flap.