In my post regarding draining my boiler condensate a few posts down from this one ( ) I'm looking at stuffing a 1-1/2" ABS trap between the studs.

Not so much for aesthetics, but for space conservation -- it's a cramped utility room and I need to keep the washer/dryer stack close to the wall.

I've dug up some posts here that say I "can't" put a trap in the wall, and others that say (specifically) a sink's trap "shouldn't" be in the wall. And of course I've got my laundry trap buried between the studs, and my shower trap below the floor, so...

For my trap, I'm planning a cleanout right above the entry point, where the condensate drips in. I figure I have options:

- cut an access hole in the wall to get to the cleanout, or
- put an access panel over this section of wall, or
- "box out" this section of wall with drywall, leaving the trap and its connections exposed and accessible.

Words of wisdom? Preferences? Again, looks aren't important since a washer will be parked in front of it.