In looking at how to do the drain routing for my bathroom remodel, I realized it's more problematic than I thought it was because of doubled-up I-Joists, and would appreciate advice on the best route to proceed. I'll run this by the inspector, who's been very good about talking with me about what they expect with water column tests etc for remodels, but would appreciate advice from others for what the best path to ask for should be.
I'm relocating the bath and shower. Previously they both shared a single drain (bath drain running horizontally to vent wye then shower) but in the relocation only the shower is really positioned to use that drain well.
My first thought had been to route the new tub drain into the 2" horizontal drain coming from the laundry group---it's in the same joist cavity, the DFUs work fine, and I can bring a vent in to vent the tub vertically before it runs horizontally without any problem. But in my first conversation with the inspector he said it wasn't OK to share that horizontal drain with the laundy and it needed to be shared with the shower. I had the impression he viewed this as a general workmanship issue, rather than a DFU issue, though I can't find any code or discussion of such, so I'm wondering if he misunderstood about the venting question---VA code (mostly IPC I think) only allows horizontal venting withing bathrooms, but I don't know of a restriction on sharing a drain line if each fixture is vented separately (in this scenario the laundy group is common vented before turning horizontal).
So following on the inspector's request to share a drain between the tub and shower, I planned on running the tub drain over to the shower. The challenge here is I have to cross 5 joists---and because the original builder didn't follow the blueprint properly (they used 14" joists instead of 16"), the joists are doubled up, so running a drain perpendicular through 5 pairs of joists is going to involve a lot of little pieces since the spaces between them are very narrow.
The two options I've thought of here are flexible PVC and running the drain diagonally. FlexPVC from what I can tell is sometimes allowed by inspectors but isn't technically a DWV product---I'm hesitant to propose its use in a sealed ceiling. Running the drain diagonally (which is the direction it needs to go) would help a bit with the number of little pieces I need as I think with diagonal holes I could get a bit longer pieces of PVC in between the joists, but it would also look ugly, or at least unusual (though it's sealed, so no one will see it in the future).
There's another option of running the tub straight to the main 3" horizontal building drain and patching it in there. I'd really hoped to avoid that as I figure if I'm only working in branch drains the blast radius of any problems/mistakes is at least contained, but maybe adding a wye and fernco to the building drain isn't that risky of a thing and better than running the drain through the joists anyway.
So facing a choice between trying to persuade the inspector to let me use the laundry drain for the tub, asking for approval for flexpvc, running a pvc line diagonally through doubled joists, or bringing a separate drain line into the building drain, I'd appreciate advice for which is the best choice.
Thanks,
Bruce
I'm relocating the bath and shower. Previously they both shared a single drain (bath drain running horizontally to vent wye then shower) but in the relocation only the shower is really positioned to use that drain well.
My first thought had been to route the new tub drain into the 2" horizontal drain coming from the laundry group---it's in the same joist cavity, the DFUs work fine, and I can bring a vent in to vent the tub vertically before it runs horizontally without any problem. But in my first conversation with the inspector he said it wasn't OK to share that horizontal drain with the laundy and it needed to be shared with the shower. I had the impression he viewed this as a general workmanship issue, rather than a DFU issue, though I can't find any code or discussion of such, so I'm wondering if he misunderstood about the venting question---VA code (mostly IPC I think) only allows horizontal venting withing bathrooms, but I don't know of a restriction on sharing a drain line if each fixture is vented separately (in this scenario the laundy group is common vented before turning horizontal).
So following on the inspector's request to share a drain between the tub and shower, I planned on running the tub drain over to the shower. The challenge here is I have to cross 5 joists---and because the original builder didn't follow the blueprint properly (they used 14" joists instead of 16"), the joists are doubled up, so running a drain perpendicular through 5 pairs of joists is going to involve a lot of little pieces since the spaces between them are very narrow.
The two options I've thought of here are flexible PVC and running the drain diagonally. FlexPVC from what I can tell is sometimes allowed by inspectors but isn't technically a DWV product---I'm hesitant to propose its use in a sealed ceiling. Running the drain diagonally (which is the direction it needs to go) would help a bit with the number of little pieces I need as I think with diagonal holes I could get a bit longer pieces of PVC in between the joists, but it would also look ugly, or at least unusual (though it's sealed, so no one will see it in the future).
There's another option of running the tub straight to the main 3" horizontal building drain and patching it in there. I'd really hoped to avoid that as I figure if I'm only working in branch drains the blast radius of any problems/mistakes is at least contained, but maybe adding a wye and fernco to the building drain isn't that risky of a thing and better than running the drain through the joists anyway.
So facing a choice between trying to persuade the inspector to let me use the laundry drain for the tub, asking for approval for flexpvc, running a pvc line diagonally through doubled joists, or bringing a separate drain line into the building drain, I'd appreciate advice for which is the best choice.
Thanks,
Bruce
