Over slab: max step up, trap locn

[rerickson]

We'd like to install a shower over an existing slab floor; 9 feet from the shower drain, the slab ends and there's a good drop to existing lines. (Unfortunately the only window, in a load-bearing wall, prevents locating the shower at the slab edge. No closer drain is available unless we tear apart the soil stack.)

By my computations, we'll just clear the sill plate with a 2" line at minimum slope, provided its centerline is 5" above floor level at the shower drain.

1. Is it reasonable, and Code, to raise the shower pan 6" or so above floor level? (It appears our pan's entry rim will be another 4" above that.)
Placing a step before the shower would mean raising the toilet as well. (It's a small bathroom.)

2. Can the trap be located nine feet from the fixture, prior to connecting it to anything else? How tightly against the pan might we expect to be able to bring out the drain line, with or without a trap there?

3. Is it permissible to remove a short slice of the sill plate, bolting the ends to the cement? That would lower everything by 1-3/4".

The vanity is against the exit wall; on the other side is the laundry. There's plenty of drop below the laundry wall.

Thank you for any advice you can offer!

 

[rerickson]

P.S. I'm reluctant to use a drain pump, because of the likelihood of hair tangles. There are also doubts as to whether the local bldg inspector will approve one.

 

[Reedwalker]

Im not sure I follow what you're saying but as far as #2 goes plumbing code states that a 2" horizontal drain line cannot exceed 6' away from a vented line.

 

[rerickson]

To improve the installation and simplify my question:

I would like the output of the P-trap on our new shower to be as close as possible to shower-pan level.
How small a drop is possible there?

(Clearly, the top of the outlet pipe must be below the pan. But I don't know if there are practical P-traps that allow it to be close, or if they all need a significant drop from pan to top of outlet. Every inch matters.)

Background: Shower is on existing slab. I'm reluctant to saw a slot through the slab for the entire drain line, given that this is inside an occupied house. (Heavy equipment, wheelbarrows of debris, wheelbarrows of cement.)
On the other hand, routing the drain line above the sill plate will give my shower pan a height above 6", which isn't great.
I'm hoping to compromise, by boring and chipping the cement only as much as needed to route the drain line just below the sill plate. At 9' of run with 2" line, this puts my shower pan height at 4-1/2" plus the pan-outlet gap.