WoodenTent
New Member
So this is really a question about a logic flaw in IRC code, but I'll cover my issue first.
My 1950s ranch has a 2x6 non-load bearing wet wall. Coming from the basement and passing up thru to the roof is the main stack/vent (it's 1 story house, so the area of concern it's just a vent). The roof has a valley above this wall. The original vent went right into the valley (near the base where the rafters/ceiling joist, exterior wall, and this wet wall all meet. So that was a flawed design, so the vent pipe penetrating the roof needed to be moved. But there is no space above the top plate to make the turn to go away from the valley. The only way to shift the 3" vent over was to shift over one stud bay so there was space above to turn. This leads to the need to have a 3" vent pass thru 1 non-load bearing 2x6 stud.
But this is where Code has a logic fail, and I'm thinking there is something missing here. So Code IRC2015 states a non-load bearing stud can be drilled 60%. On a 2x4 wall, this would allow a 2.1" hole, leaving 1.4" of wood. This is also consistent with code allowing non-load bearing walls to be framed with studs put flat (1.5" thick of wood. But when you jump to a 2x6, the 60% rule would allow 3.3" hole, leaving 2.2" of wood. This is where the logic fails. You put in a wider wall, and yet have to leave more wood, even though it's non-load bearing. You would think instead of percentage, that would have it be 1.5" of wood must remain, with hole centered in wall. This would then allow for a 3" PVC (3.5" OD) with room to spare. Instead it is a no go. Something seams wrong/missing here.
You can buy a Simpson stud shoe for a 2x4 which will allow you to drill a 2.5" hole to run a 2" pipe thru a load bearing wall. But you can't drill for a 3" PCV thru a 2x6 non-load bearing wall. Additionally no one I have found makes a stud shoe for 2x6 to allow a 3.5" hole. Which would seam like something they would make. So is the end answer that inspectors of the world just look at such things and say "good enough". Am I missing something in the books, I've never found a line in IRC2009 or 2015 that comments on this.
Obviously not a lot of times for 3" pipe running horizontally in a wall. But that's not an excuse for the issue since it will be something that comes up. I live in an area with thousands of houses with the same basic layout as mine, thus same basic flaw (vent in the valley leads to leaks/rot). People may come up with all sorts of work arounds, but in the end sometimes you just have to put a 3" pipe thru a 2x6 non load bearing wall stud.
What is the common practice here, and or is there a exception in code I have missed?
My 1950s ranch has a 2x6 non-load bearing wet wall. Coming from the basement and passing up thru to the roof is the main stack/vent (it's 1 story house, so the area of concern it's just a vent). The roof has a valley above this wall. The original vent went right into the valley (near the base where the rafters/ceiling joist, exterior wall, and this wet wall all meet. So that was a flawed design, so the vent pipe penetrating the roof needed to be moved. But there is no space above the top plate to make the turn to go away from the valley. The only way to shift the 3" vent over was to shift over one stud bay so there was space above to turn. This leads to the need to have a 3" vent pass thru 1 non-load bearing 2x6 stud.
But this is where Code has a logic fail, and I'm thinking there is something missing here. So Code IRC2015 states a non-load bearing stud can be drilled 60%. On a 2x4 wall, this would allow a 2.1" hole, leaving 1.4" of wood. This is also consistent with code allowing non-load bearing walls to be framed with studs put flat (1.5" thick of wood. But when you jump to a 2x6, the 60% rule would allow 3.3" hole, leaving 2.2" of wood. This is where the logic fails. You put in a wider wall, and yet have to leave more wood, even though it's non-load bearing. You would think instead of percentage, that would have it be 1.5" of wood must remain, with hole centered in wall. This would then allow for a 3" PVC (3.5" OD) with room to spare. Instead it is a no go. Something seams wrong/missing here.
You can buy a Simpson stud shoe for a 2x4 which will allow you to drill a 2.5" hole to run a 2" pipe thru a load bearing wall. But you can't drill for a 3" PCV thru a 2x6 non-load bearing wall. Additionally no one I have found makes a stud shoe for 2x6 to allow a 3.5" hole. Which would seam like something they would make. So is the end answer that inspectors of the world just look at such things and say "good enough". Am I missing something in the books, I've never found a line in IRC2009 or 2015 that comments on this.
Obviously not a lot of times for 3" pipe running horizontally in a wall. But that's not an excuse for the issue since it will be something that comes up. I live in an area with thousands of houses with the same basic layout as mine, thus same basic flaw (vent in the valley leads to leaks/rot). People may come up with all sorts of work arounds, but in the end sometimes you just have to put a 3" pipe thru a 2x6 non load bearing wall stud.
What is the common practice here, and or is there a exception in code I have missed?
