Not a Pro
April 21st, 2005, 01:29 PM
I've run into a situation beyond my experience and knowledge, and could use some help. My 80 year old house is single story over basement. The existing DWV is 4" CI (HD/SD?). During a refurbish/remodel, the CI will be replaced with 3" PVC and/or hubless CI, down to the existing Wye and c.o. just above the basement floor.
In the existing system, the discharge from the WC does NOT turn horizontally with a closet bend, but instead is directly above/on top of the vertical soil stack. Approximately 20" below the WC is a 4x4x4 Wye, with the vent stack angling off at a 45 degree angle up and away from the vertical soil stack until it has moved 18" to the "rear" of the WC and the 2x4 wall behind it. An 1/8 bend then turns the vent stack to go vertically up through a back corner of a hallway linen closet, then through the attic and the roof.
After the remodel, coming from opposite directions will be a pair of 2" horizontal branch lines under the 2x8 floor joists, serving the lav/tub and the kitchen sink. (Both will be re-vented into the vent stack more than 6" above the sink flood levels.)
1.) If I duplicate the existing soil and vent stack arrangement, can the two branch lines drain into either the angled portion of the vent stack and/or into the soil stack at a point ABOVE the Wye?
B.) If I instead connect the two branches into the soil stack at a point BELOW the Wye, won't I have too much vertical drop before entering the soil stack?
III.) Alternatively, couldn't I put a closet bend under the WC and run "back" 18 inches horizontally in the joist space to a san-tee at the base of the vent stack, then use an 1/8 or 1/4 bend to run "forward" 18 inches before turning down and dumping into the vertical soil stack? The two branch lines would wye into the vertical soil stack.
4.) One of the above will be best for the tight space restrictions from a couple of HVAC ducts in the area and from my desire to keep the DWV as far up and out of the basement living space as possible -- but before I start figuring out which would be best for space considerations, which (do any?) of them meet minimum code? We're under UPC 2003. Would any that DO meet code be considered more or less desirable? Are there other ways that I haven't considered?
Thanks. NAP
In the existing system, the discharge from the WC does NOT turn horizontally with a closet bend, but instead is directly above/on top of the vertical soil stack. Approximately 20" below the WC is a 4x4x4 Wye, with the vent stack angling off at a 45 degree angle up and away from the vertical soil stack until it has moved 18" to the "rear" of the WC and the 2x4 wall behind it. An 1/8 bend then turns the vent stack to go vertically up through a back corner of a hallway linen closet, then through the attic and the roof.
After the remodel, coming from opposite directions will be a pair of 2" horizontal branch lines under the 2x8 floor joists, serving the lav/tub and the kitchen sink. (Both will be re-vented into the vent stack more than 6" above the sink flood levels.)
1.) If I duplicate the existing soil and vent stack arrangement, can the two branch lines drain into either the angled portion of the vent stack and/or into the soil stack at a point ABOVE the Wye?
B.) If I instead connect the two branches into the soil stack at a point BELOW the Wye, won't I have too much vertical drop before entering the soil stack?
III.) Alternatively, couldn't I put a closet bend under the WC and run "back" 18 inches horizontally in the joist space to a san-tee at the base of the vent stack, then use an 1/8 or 1/4 bend to run "forward" 18 inches before turning down and dumping into the vertical soil stack? The two branch lines would wye into the vertical soil stack.
4.) One of the above will be best for the tight space restrictions from a couple of HVAC ducts in the area and from my desire to keep the DWV as far up and out of the basement living space as possible -- but before I start figuring out which would be best for space considerations, which (do any?) of them meet minimum code? We're under UPC 2003. Would any that DO meet code be considered more or less desirable? Are there other ways that I haven't considered?
Thanks. NAP