curiosity ... Why are tub drains designed to require a slot in the floor?

Users who are viewing this thread

Tbbarch

Member
Messages
77
Reaction score
1
Points
8
Location
Virginia
I'm studying a tub installation and am wondering why tub drains do not go straight through the floor instead of doing a 90 requiring cutting a slot out of the floor.

Couldn't the lateral just as easily be below the floor?
 

hj

Master Plumber
Messages
33,599
Reaction score
1,037
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
quote; Couldn't the lateral just as easily be below the floor?

OF course, but then you would have to make a box under the ceiling for the "P" trap. It would be easier if you just turned the tub so the joists were parallel to the drain line. Or, if you do not want to turn the tub, have the framers run the joist the other way.
 

Tbbarch

Member
Messages
77
Reaction score
1
Points
8
Location
Virginia
So ... the entire point is to not have a trap hang into a possible ceiling below?

That 1" of added pipe would not seem to make that happen.

As I said it is a curiosity. It looks like the drain stopped evolving after footed tubs were made into apron tubs.
 

Asktom

Member
Messages
745
Reaction score
32
Points
18
Location
Victor, MT
The current configuration allows for a simple trip lever stop. The real question is why is the drain in the center so there is a floor joist in the way 1/2 the time. The drain should be set to one side or the other to avoid this problem. Then there would be left hand tubs with left side drains, left hand tubs with right side drains, right hand tubs with right side drains and right hand tubs with left side drains. That would simplfy things.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,946
Reaction score
3,460
Points
113
Location
Bothell, Washington
Website
terrylove.com
The current configuration allows for a simple trip lever stop. The real question is why is the drain in the center so there is a floor joist in the way 1/2 the time. The drain should be set to one side or the other to avoid this problem. Then there would be left hand tubs with left side drains, left hand tubs with right side drains, right hand tubs with right side drains and right hand tubs with left side drains. That would simplfy things.

Yes. Because it's so hard for designers to figure this stuff out. And framers............they have to read a blueprint. But no worries, let the plumber bring out several tubs and one of them might fit. It's no big deal putting a couple tubs on your van just in case the framers moved the drain location again.

Or heaven forbid, someone read the gosh darn plans and frame it for a tub like they're supposed to.
 

Asktom

Member
Messages
745
Reaction score
32
Points
18
Location
Victor, MT
I once worked for a plumber whose solution was to start up a gas chain saw - that always brought the carpenters sprinting over to change it any way he wanted.
 

hj

Master Plumber
Messages
33,599
Reaction score
1,037
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
quote; That 1" of added pipe would not seem to make that happe

That is similar to my solution on one job. It was a 156 unit motel and the flooring was 1 2/8 plywood, and it was the rough and finish flooring. We had to remove a section to install our plumbing under the floor so I asked the carpenter foreman, who happened to live right behind my house, to cut a section out and then replace it after we were done. He said it was the plumber's job to cut the floor, so I told him I would do it, but he was not going to be happy with HOW I did it and he was still going to have to repair it, somehow, afterwards. HE decided to cut the floors.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,946
Reaction score
3,460
Points
113
Location
Bothell, Washington
Website
terrylove.com
As a plumber you must be aware that s#@t flows down hill.

And as a home builder in the 80's submitting my own plans for permits and to the engineering department, it was a simple matter of knowing how things went together.
I was the first one in the city of Bellevue to submit building plans done on a CAD system. At Lake Washington Vo-Tech I was helping architects learn CAD. I was doing a lot of Passive Solar at the time. The largest builder in the area at that time came over on a Saturday and tape measured one of my homes. Nine months later, elements that I had come up with showed up in their homes. That same home they had looked at was re-sold to a home builder that used it for his personal home. He wanted plans for the home, and in 1992 offered to hire me to work with him. There were a lot of things about construction that I knew, that he was curious about. He's still in business building large custom homes, and I decided to keep with plumbing. There is always work for plumbers, even when interest rates go up and down, and bubbles burst. I left homebuilding in 1988.



lot1b.gif


1983, Bellevue

Journal American Home of the week

lot18_1.jpg


1987, Woodinville WA

becu_900.jpg


The Boeing Employee's Credit Union.

I plumbed this job in 1989

The blueprints showed a 4" high staircase between the lobby and the second floor where my 8" cast iron rain drains were going. I'm 6'-1", and I thought that was a little short for stairs. I tried to explain to the carpenters setting the forms, but they didnt' understand the problem. It's a math and spatial thing. I got them to send the plans back to the
architects. The revison was even worse. So......I marked up the plans real good, and sent it back. The third set of drawings were correct, and I have the framers permission build out the second floor. Mind you, I'm the plumber. But this happened all the time during my construction career. I can walk though plans in my head as easily as if they have alread been built.
The stairwell in that building is where the pre-stressed cables were tying in. If they had built to the first set of plans, they would have had to tear out most of the second floor.

 
Last edited:

Absaroka Joe

New Member
Messages
6
Reaction score
0
Points
1
Location
CO
I'm studying a tub installation and am wondering why tub drains do not go straight through the floor instead of doing a 90 requiring cutting a slot out of the floor.

Couldn't the lateral just as easily be below the floor?


Watco makes this fitting. It can be handy sometimes when the top flange of an engineered joist is in the way. You can drop down vertically and then go through the joist web. It needs to be at least a 12" joist to have room for the trap.
 

hj

Master Plumber
Messages
33,599
Reaction score
1,037
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
IF you are really concerned about it buy a "raised floor tub" which has room under it for the drain. The side of the tub is 2" higher even though the tub is the same depth.
 
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