venting question...

[jeffreypca]

Doing a remodel on 1900 old house. Can I replace main stack with a couple smaller vents?

[hj]

Practically yes, "legally", code wise, maybe. It depends on how your local code is written. And then there are usually requirements as to the sizes of the smaller vents and HOW MANY are needed to replace the larger one. That also depends on the interpretation of the code, for example, if the code says the "sizes" have to add up to the size of the original, then that could mean two 2" pipes were sufficient to replace a 4" one, but if it says the "areas" have to be equal, then it takes four 2" pipes.

Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

[jimbo]

Where you live also matters. Around here ( southern Calif) we rarely see single large vents. Much more likely to see a couple of 2's and a couple of 1½'s, something like that. But if you are in a freeze area, small vents can frost over, and code may require a full size pipe through the roof.

[TDVT]

I just reconfigured my venting, running 2-2" vents & a 1 1/2" vent through the interior of the house but the joined each of them separately into a single 3" section in the attic using the existing pipe through the roof. Made the venting in the walls MUCH easier & no new holes to the outside.
I'm not sure where you are located but we get ALOT of snow here & something smaller would almost surely freeze up.

[jeffreypca]

well, i am up in ontario, canada. So I will have to check with a plumber around here because we have pretty cold weather. Thx everybody for feedback.

[TDVT]

Not to say you couldn't have multiple vents, you just might want to up-size where it goes to the outside since you're in cold weather.

[jeffreypca]

If I look at newer houses around here, they all have a bunch of 2" vents and no big 4"...