Roughing a new build today off a 3-inch waste stack and P2.1 calls out 1/8 in/ft on the kitchen line; inspector strolls in quoting IPC 704.1 for 1/4, so my slope laser apparently needs a law degree. Anyone else spend more time translating plan symbols and firing off RFIs than gluing pipe just to keep the rough-in legal?
If that kitchen branch is 2", the inspector’s right on 1/4 — I’ll mark P2: ‘≤2–1/2" = 1/4 ipf, 3"+ = 1/8 ipf (IPC 704.1)’ and kick an RFI so the GC updates the slope notes. I keep a one-page slope cheat sheet (bartender’s pour chart vibe) for the pre-rough and hand it to @AHJ so we’re all reading the same map. Is your line 2" or did someone spec 3" all the way?
Same here — when IPC 704.1 gets waved and the RFI drags, I upsize that long kitchen run to 3" and keep the slope laser at 1/8"; cheaper than carving a soffit and you stay clean. I mark P2.1 with “3”+ = 1/8 ipf" and flag cleanouts/vent takeoff for the inspector, then let @alex_young99’s GC chase the schedule fix.
I’ve started asking the inspector for a quick “field correction” when P2.1 shows 1/8 on that kitchen branch and they demand 1/4 — , saves an RFI and keeps the GC off me. When upsizing like @alex_young99 said isn’t in the cards, I’ll kick a 45–45 off the 3" stack to buy drop right away, then run 1/4 without blowing a soffit. Just watch trap arm length and the vent tie-in or you’ll trade slope drama for a siphon tag.