Connecting additional shower drain to an existing tub drain.

Users who are viewing this thread

Branimal

New Member
Messages
29
Reaction score
0
Points
1
Location
NYC
I just demo'd my bathroom down to the studs.

My existing bathroom had a double sink, toilet and tub. I ripped out a corner closet and i want to add a custom shower and center drain tub and install a new double sink and toilet. See last picture for old and new layouts.

Drain and vent pipes are both 1 1/2" cast iron. Copper supply pipes are 3/4" reduced to 1/2".

I think I can reposition the the new center drain tub to use the old tub's drain with the correct attachments. See 'T' in the first picture.

My question is can I attach my new shower drain to the existing tub drain? Will this give adequate drain flow.

This is my understanding of the steps:
1. Cut up floorboard area needed to access drain pipes with circular saw
2. Center drill joists with hole saw bit. The joists run at a 45 degree angle to my bathroom. Bathroom is at an angle to the building.
3. Reinforce joists with sister joists.
4. Install shower drain pipe dropping 1/4" every 12" to the tub drain. Provide proper support for pipes.
5. Put the correct connector piece on tub drain. I believe its a Wye connection. I think I need to install the Wye connection past the tubs trap. See 'X' on the first picture.
6. Test it

Now I need to vent the new shower drain. Is simply connecting the shower drain to the tub drain adequate venting? Meaning now the tub and shower drain share the tub's original vent line See 'V' in first picture. Or should I install a Tee or Wye further up the tubs vent line and attach the shower vent? See 'Y' in the second picture.

Third picture is for reference --> 'D' drain, 'V' for vent
 

Attachments

  • IMG_3535 (1).PNG
    IMG_3535 (1).PNG
    83.6 KB · Views: 501
  • IMG_3536 (1).PNG
    IMG_3536 (1).PNG
    48.9 KB · Views: 452
  • IMG_3559 (1).PNG
    IMG_3559 (1).PNG
    50.6 KB · Views: 568

Branimal

New Member
Messages
29
Reaction score
0
Points
1
Location
NYC
Heres the old and new layouts
 

Attachments

  • IMG_3534.JPG
    IMG_3534.JPG
    79.5 KB · Views: 553

Sylvan

Still learning
Messages
2,751
Reaction score
685
Points
113
Location
New York
Are you sure the cast iron under ground is 11/2"

NYC plumbing code 1938 stated under ground drain piping "shall be 2" min" fast forward to the 1968 NYC plumbing code "under ground waste lines and drainage lines "shall be 2" min"
 

Branimal

New Member
Messages
29
Reaction score
0
Points
1
Location
NYC
The drain pipe at the tub is 1 1/2". But about 6" below the tub drain pipe it seems to get larger ~ 2". I cannot reach down there and measure.

The vent lines are 1 1/2".
 

CountryBumkin

Active Member
Messages
915
Reaction score
70
Points
28
Location
Orlando, FL
Tub drains are 1-1/2" and Shower drains are 2".
I asked here why, and the logic/reason given was that since the Shower has much lower ledge/side and could overflow more easily if there was some drainage restriction. The larger pipe adds a higher safety factor.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks