Bathtub vent and drain questions

[Lordoftheflies]

Hello,

Been a while since I posted but I figured I'd post and make sure before I proceed any further. This is the 2nd (top) floor bathroom in a cape cod.

Doing the drain and vent for my 32" x 66" bathtub. There's two joists butt up against the drain since the original framing was done for a 30"x 60" bathtub. It just squeeze by but basically blocks off one side to route the venting.

I just wanted to make sure I did this right. I think I did (knock on wood).
here you can see the layout. I caught myself before I made a mistake with the vent. Originally was going to tie it into the drain horizontally and then my brains kicked in and I realized that was a big no no.

Here you can see the joist butt up against the drain.

Tied into the existing 1.5" copper with a no hub rubber connector that connects to the 4" CI main stack.

I used a sanitary tee to connect to the trap and then used a 45 elbow to another 45 elbow to connect to the vent. This is a dedicated vent for the bathtub.

This is a large tub (22" or 24" deep I can't recall atm) and has a capacity of 70 gallons. The drain that was included was 1.5" so I went with 1.5" for the drain and the vent.

I'm going to use a long sweep 90 below the trap.

Originally was going to use this closet space to make some shelves perhaps but in the end I decided it was better put to use just as an access point to the tub and controls. If I ever need to get into the space it will be easy to access. I'll bring up the 1" PEX water lines (1" for maximizing the volume to reduce fill times for the wifey when she takes a bath) and plus the space was quite small anyways.

Please don't hesitate to tell me I did something wrong.

 

[Lordoftheflies]

Here is a picture from underneath. I don't think I would have had room to turn the trap and bring the vent up the other side and plus I'd have to redo the connection to the vent up top.

 

[Sponsor]

 

[Terry]

That should all work for you.
Normally the waste and overflow is 1.5" and the p-trap.
At the santee it normally goes to 2". I assume since it's an old Cape Code that you're going to 1.5" and you don't have 2" to run to?

 

[Lordoftheflies]

Thanks Terry.

I can transition to 2" actually. I put in a 2" santee right below the toilet tee at the main stack when I transitioned to PVC for the toilet.

That said, do I have to have the vent also in 2" for it to work efficiently or should I just leave it all at 1.5"?

My plan is to create a soffit above the doorway to run the pipe across the room. I have 2x8 joists which I had to sister because the original plumbers notched the 2x8 down leaving only 1" of wood for the toilet drain (smh). They also had notched every joist between the toilet and the bathtub so I had to sister those as well (glued and screwed).

Running the bathtub drain down below the joists also allows for the 1/4" drop per foot...The drain will be 6.5 feet away so that means I'd have to drop 1.5". I don't think you're supposed to drill a hole too close to the bottom of a joist, correct?

Once I finish the upstairs bathroom I'll think about doing the 1st floor bath. Then will be the time to remove most of the remaining CI stack and replace with PVC. I'll have to figure a way out to vent the toilet...but since the toilet, the vanity, and the tub are all on the same wall I think they can share and I can tap into the existing vent I had run for the existing vanity.

Here's the 2" santee at the stack.

Here's the space above the door where I'll run the drain from the bathtub to the stack as well as water to the vanity for the upstairs bathroom. I'll be cutting that 1" pex short and transitioning to 3/4" and then 1/2" for the toilet and the sink.

Here you can see the cleanout for the upstairs bathtub trap.

And here's where I transitioned from galvanized to pvc (2") for the existing vanity. The original galvanized went straight up into the middle of the upstairs bathroom (there used to be a wall for a walk-in closet that I removed so I had to move the vent).

On another smh note whomever worked on this bathroom over the years (built 1947) just layered and layered on the sheetrock instead of gutting the bathroom. Downstairs bath barely has a lip on the ends. They also screwed up the stack and ended up using 3/4" shims before the first layer of sheetrock was installed!

 

[Terry]

For the tub, 1.5" for the trap and for the vent.
After the vent, 2" is what we like.

Drilling any joist, you need to leave 2" on the top and 2" on the bottom.
Yep, 2x8's suck.

 

[Lordoftheflies]

Thanks Terry.

Then I will transition to 2" starting from the santee at the vent connection.

I will go with routing the drain below the joists. I had an engineer come and help me draw up a plan of action regarding the terrible joist botching and the first thing he did was shake his head in disgust at the 2x8 calling the original builders cheap $(#&^$#*(&^Y@#s.

The people who installed the central air before my time cut out the base plate 2x4 to run the ac ducts to the bathrooms.....This in turn caused all the weight of the 2nd floor and the first floor to be supported by 2x8 in the basement.....which of course were split. I literally caught all of this in the nick of time and in my "Complete Bathroom Remodel Post#60/61" thread I have pictures where I glued the splits, sistered new joists, used an automotive jack and a long 2x4 to repair the existing joists, and installed double width 2x8 joist hangers.

Perfect example of opening up a big ol' can o' worms!

Thanks again Terry!

 

[Lordoftheflies]

Also just want to make sure that using a long sweep 90 post santee is the way to go. After that elbow I can transition to 2".

 

[WorthFlorida]

......Running the bathtub drain down below the joists also allows for the 1/4" drop per foot...The drain will be 6.5 feet away so that means I'd have to drop 1.5". I don't think you're supposed to drill a hole too close to the bottom of a joist, correct?

https://www.co.lincoln.or.us/sites/..._-_helpful_hints_residential_construction.pdf

Go to the 4:56 time mark

 

[Lordoftheflies]

Thanks WorthFlorida.

Here's what I did today - transitioned to 2" below the santee, long sweep 90 then another long sweep 90 to turn towards the main stack.

Used j-clamps to secure the 2" pipe. The top of the pipe is at 5.5" down from the floor joist at the main stack and it's at 2.5" at the end of the straight shot.

Love those j-clamps since they click and lock the pipe. That sucker ain't moving.

Also bought two metal riser clamps to secure the vent pipe both above the wall plate in the roof as well as at the vent connection flush to the subfloor at the tub.

I tested a little bit (not the real test I know) with a 5 gallon home depot bucket and didn't have any leaks so I'm pretty excited about that. Woot!

Thanks everyone for the help.

View attachment 53032

 

[Lordoftheflies]

As usual I had a brain fart and initially used a 1.5" long sweep 90 before I realized I was an idiot. Hence the coupling.

 

[Lordoftheflies]

Here's a better side view of the slope.