Can I run a 2" vent pipe through multiple studs ?

Question

The studs are to the exterior wall causing them to be load bearing. the original owner did it in one of the studs to run the vent from the kitchen sink using a steel box style suppport. can i use pvc instead of re - running steel in this replacement section?

Answer 1

First off, use logic.  And always ask yourself "did the last guy do it right or just get lucky?"

   Then you got to ask yourself "how lucky do you feel?"

"Well, punk;

How lucky do you feel?"

The steel is replacing the wood that was cut out / strength for strength

It was a mistake to cut thru a load bearing stud(or beam)  You just don't do it.   Load bearing means it carries everything above it(which could be the second story and the roof)  Avoid the studs.  It is a vent  pipe.  Air will go around corners.

Answer 2

It depends on your stud depth. Schedule 40 PVC DWV has an outside diameter of about 2.375 " (2-3/8").

The IRC allows boring of load bearing studs, within limits. A hole in a load bearing stud shall not exceed 40% of the stud's depth; that means a 2x4 stud can drilled no more than 1-25/64". Now for the exception to that rule; IRC R602.6, Exception #1 states "A stud may be bored to a diameter not exceeding 60% of its width, providing that that such studs located in exterior walls or bearing partitions are doubled and that not more than two successive studs are doubled."

Clearly, neither of these rules helps with 2x4 walls. If you have 2x6 framing, a 2" PVC vent arm could be used; either by doubling the studs, or by installing an approved "Plumbing Shoe", per Exception #2 to R602.6. The Code does not clearly state (2003 IRC) that there is a limit on how many successive studs can be repaired with these shoes. Generally, the Plumbing Code will place a limit on the horizontal length of the vent.

The answer to the question is "It depends on what the conditions are on site.", and what your local Inspector says.

Answer 3

I would've avoided notching or drilling a load-bearing wall.  If you're in a cold climate you don't want piping in an exterior wall anyway.

If possible, it wouldn't hurt to plywood over the studs (be generous with nails) before sheet-rock.  It would add back a little support.