Question - Freestanding Tub Drain over Floor Joist

[wwhitney]

The drain assembly that comes with the tub has 1.5" threads that accept the nut and flanged tailpiece provided with the drain kit.

So what type of threads are those, and is there a 45 degree elbow available with those threads? I'm assuming not Schedule 40 threads.

If the OP has access from below, the drop in kit is not required. And then a pair of 45 elbows could jog the the tailpiece over to probably avoid the joist. A test fit would be required to be sure.

Cheers, Wayne

 

[amcculidis]

Good evening,

I have an update and some follow-up questions to my original post. The construction has begun this week. Our GC had his plumber add the tub drain and drop-in drain kit right in the joist (making me think I could have done that). Today the GC installed headers around it. I came home and noticed one of the headers is notched about 50%. The header are about 9 inch apart. We are told that a inspector is coming in the next 2 days and the GC doesn't seem concerned. Could anyone clarify if/how this is OK?

 

[Sponsor]

 

[wwhitney]

I wouldn't like that, and it violates the IRC's prescriptive language on notches and holes in joists. It was completely unnecessary, too, as it seems like there's enough height to leave the required 2" of wood above the pipe. So the header should be replaced with a new piece with a properly drilled hole.

https://up.codes/viewer/north_carolina/irc-2015/chapter/5/floors#R502.8

Now to be honest, if your GC were an engineer, he could probably do the calculations to show that for a header carrying just one floor joist, a 2x4 or 2x6 would suffice, and so instead of installing a notched member like that, they could have used a tell tall member (which might actually be stronger, the square corner of the notch leads to a stress concentration).

But your GC is probably not an engineer, so he needs to follow the prescriptive codes requirement cited above.

Cheers, Wayne

 

[amcculidis]

Hi!

I inquired our GC and he texted "This joist rest on wall, header it's additional support, have inspection today". Aren't all joists rest on walls? The inspector came and according to my husband he said it is acceptable "because of where it is relative to the other supports". I can't tell if he's trying to emphasize there's no concern or to avoid elaborate steps to fix it. I'm a little confused and frustrated. I have attached the picture indicating where these joists/headers are located (in red dot). This is not our house but it is almost identical.

 

[wwhitney]

The question is, how long is the floor joist that the notched header is carrying? If it's only 1' to 2' long because it's right near the wall, then the notch is a non-issue. There's nothing spelled out in the prescriptive code in the IRC that would allow the notch, and the inspector and GC are just using "gut" engineering to okay it, but I would say they are correct:

A single short joist, at say 2' long, has a load on it of at most 50 psf * 2' long * 2' wide (if joists are 24" o.c.), or 200 lbs, and the header receives half that load, or 100 lbs. It has to distribute it to the two ends, 2' away, 50 lbs at each end. Even with the notch I would expect it can do easily; and if the framing is 16" o.c. the load is even less.

If the floor framing is still open as in the photos, you can do a little test by putting your full weight on the header at the edge of the notch, and seeing if it feels at all bouncy or if anything creaks or moves. It shouldn't.

Now if the notched header is carrying the other end of the joist, that bears on the wall 10'+ away, that's a different story, and it should be fixed. My initial answer was based on that case, even though with further consideration I realize it is more likely to be the < 2' long case.

Cheers, Wayne

 

[Jeff H Young]

that 2 foot long head out is full bearing on top plates below you can see it in pictures I'm thinking there's gotta be a wall right there?. Personally wouldn't worry about it but that's based on little structural knowledge just worked a little here and there with my brother who is very knowledgeable 35 year carpenter / framer

 

[amcculidis]

Good evening, Wayne & Jeff -

Thank you so much for your knowledge and feedback, Wayne & Jeff. I wish our GC would have explained it to me like you all did. I feel much better now. Have a nice peaceful weekend!