Plumbing – Does a plumbing vent need to penetrate the roof? (Can it penetrate a wall?)

draindrain-waste-ventplumbing

We're going to move our washer/dryer to the garage (the front loader needs to sit on concrete to keep it from shaking our house to the ground).

I'll need to add a washer drain to the garage for the washer. Because this will need a p-trap, my understanding is that it also needs to be vented.

I could go straight up into the attic then through the roof, but my question is: do I need to actually go through the roof? Could I instead have it go into the attic then 90 degree it out to the back, second floor wall? I can't find any particular code rules on if it has to penetrate the roof or not. This is a septic system, if that matters.

The reason for trying to avoid the roof is that I'd prefer to not climb up onto the roof…it's about 45 degrees and in the PNW so perpetually wet and mossy.

Best Answer

No problem, as long as the vent meets the criteria listed below.

  • Not directly below a door, openable window, or other air intake opening (of this or any other building).
  • Not within 10 feet horizontally of the above mentioned openings, unless it's 3 feet above them.
  • Not less than 10 feet from the property line.
  • Not less than 10 feet above the ground.
  • Not under the soffit, if soffit vents are used (Covered by point 1 in my opinion).
  • Must be protected from birds and/or rodents blocking it.

International Plumbing Code 2012

Chapter 9 Vents

Section 903 Vent Terminals

903.5 Location of vent terminal.
An open vent terminal from a drainage system shall not be located directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, and any such vent terminal shall not be within 10 feet (3048 mm) horizontally of such an opening unless it is 3 feet (914 mm) or more above the top of such opening.

903.6 Extension through the wall.
Vent terminals extending through the wall shall terminate at a point not less than 10 feet (3048 mm) from a lot line and not less than 10 feet (3048 mm) above average ground level. Vent terminals shall not terminate under the overhang of a structure with soffit vents. Side wall vent terminals shall be protected to prevent birds or rodents from entering or blocking the vent opening.

And don't forget, if required you have to protect any extensions from freezing.

903.7 Extension outside a structure.
In climates where the 97.5-percent value for outside design temperature is less than 0°F (-18°C), vent pipes installed on the exterior of the structure shall be protected against freezing by insulation, heat or both.

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