Plumbing Question for People Smarter than Me

[John Goodin]

Here is the situation. New home construction. The tub was not set until after drywall. The tub drain plumbing comes out the foundation in the stud bay beneath the mixing valve. A post tension cable blocked proper routing of the drain from the tub to where it enters the slab. The plumber used a 45 degree elbow to go over the cable creating a small uphill climb in the drain. This basically created a belly from the tub drain to the 45. On a plane, the top of the 45 appears to be close to the bottom of the tub. Is this acceptable?

I would think this would be an area for debris to collect, eventually cause a clog and that the tub would drain slower. However, my experience with building code is that there are enough “exceptions” that I may have missed something.

[Maurice Mcmurry]

That does not sound ideal. I see negative pitch drain pipes fairly often. Some cause problems. Some work fine. Can you do a test run and see how well it drains or if there is a "glug glug" while draining?

[Bill Dufour]

New home. ask building inspector. no way that meets code. Builder is responsible for delivering a legal house that meets code in force when it was built. that one is not legal.

Inspector missed it, needs to red tag the home, so sale is voided until fixed.
BillD

[George Yetka]

bath-trap-diagram.jpg

The whole thing gets a trap so it will store old bath water either way. But if the bath doesnt drain completely then its a problem. Or if its slow to drain.

they couldnt go left or right?

[Bill George]

The right answer as posted above call the plumbing Inspector, easy answer try dumping a little water in the tub and see what happens.

[Maurice Mcmurry]

If it fails, and the geometry allows, your plumber should be able to solve it by creating a deep trap. Do not use the street ell that comes with the trap. Use a piece of pipe instead, then a regular ell when the needed height is achieved.

[Bill Dufour]

How did a post tension cable block anything? They are normally inside a concrete slab. Is this a floating slab floor with a basement? Did someone jack hammer a slot into the tensioned slab. What does the structural engineer have to say about that?
It is not just the cable, it is the supporting concrete at each end of the cable to be concerned with.
That slot may have separated the monolithic slab into two pieces as far as load sharing goes. It may take a decade or two for the slab to actually crack in two.
Bill D.