Okay, I know how sewer vents are "supposed" to be run, but here's the deal... We added on to our house the whole length in the back. The new southeastern corner of the addition is the new kitchen. However, the kitchen goes through into the old part through a header in the wall. This puts our new kitchen sink on the south wall. We removed the old steel vent pipe for the kitchen sink as it was in a wall that was torn down. Can the new vent for the kitchen sink be run up inside the south wall, and be vented out the side of the gable end before going through the roof? I don't like cutting holes in the roof, if I don't have to. I saw a new construction house recently with what I think was this same situation, only for a washing machine sewer vent. My roof has a ridge vent, so there wouldn't be the problem of sewer gases going into a gable vent. The main sewer vent is through the roof in the center of the backside roof (east side). What about the possibility of just using one of those new vent caps that allow air to be sucked in, and then they spring closed again, and just use it in the attic where the kitchen sink vent would come through? Any ideas would be greatly appreciated.....