Changing tub to shower need advice

I'm changing a tub/shower to an all tile shower. I have my mud mix, liner, sealant, concrete, and a plan.
I've removed the tub to find the 1 1/2" drain pipe.
I understand that I have to move the drain to the center and build 2" to the existing trap to meet Phoenix code.
Question:
Do I need to remove the old trap and put it directly under the relocated shower drain? Or can I run new 2" to the existing trap under the old tub drain? If the trap is 1 1/2" do I have to replace it. I know these are code questions, but there may be industry wide standards I should be following.
Here's the picture of what I have now.
Thanx for your tips and advice.
Mark

Is the existing trap 2inch or 1 1/2?

You don't want to go down in size from the drain to the trap..... nor anywhere else in the system for that matter.

Got it dug-up and it's 2"

The trap is 2". I've started breaking concrete to the center of the shower, but I stopped cause I'll need a jackhammer- too much to do with a hand chisel.
It looks like I could easily cut the piece between the trap and the vent pipe and 90 it with a good line-up for the center of the shower.
I bought a new 2" trap anyway. Should I go ahead and put it under the new drain location or pop it in where the old one sets. I have to cut the old one anyway because it has a reducer to 1 1/2".

Thanx for that quick reply.

Mark

Existing P-trap

This is what I have now:

Couple of things.... considering I just finished "bustin concrete" myself to put in a new bathroom....

First, if you're going to be breaking holes, go ahead and put the trap where it belongs, below the drain.

Second, before you get that Jackhammer, be sure you score the edges of the "path" you want to take, that will give you a clean cut and help avoid cracking things you don't want cracked. I used a circular saw and masonry blade to get my outline well made, then a sledge hammer to knock out the intended path. A Jackhammer would have been a lot easier, but I'm a kindasorta masochist I guess..... and too lazy to go to the rental store...

Make your path big enough to work in, laying pipe, glueing joints, etc. especially where your new trap is going. Nothing worse than getting ready to glue and not having room to swing things properly....

Stock up on some Ben Gay.... and have fun.

Not a pro... just have fun playin like I know what I'm doin

Whoops... you posted your second photo while I was responding... Looks like you've been busy.... and it's a bit late for the "score the concrete" advice...

However, the advice still stands... if you can score the rest of your "path" you'll get a nice neat cutout... For reference, go to the "home remodel" section of this forum and check out the post "need professional critique"

I know it seems like the "best" practice to place the drain in the centre, but I've had more than one situation which required the drain to be where the old tub drain was, but offset a little bit to get it away from the wall. I've found this to work well and look good, it just means that the shorter side (between the drain and closest wall) shows more obvious slope to the drain in comparison to the longer drawn out slope on the opposite side. It looks fine, passes inspection, and works the same. mho.

Good idea

I actually like that idea better, not just because it means less work. I think it would look better too, but I was afraid it wouldn't pass. I'll be on the phone with the city tomorrow anyway, so I'll verify. But first I must get it passed by the design manager..... My wife.....
Thanx.
You guys/gals are a great help, and fast!

Mark

I'm with Kristi on this one.

I would move the trap out from the wall more, but you don't need to center it.

For other folks out there, moving and replacing p-traps is sometimes easier than using the old one anyway.

P-trap

It's not much more work for me to change it- just a little extra digging.
Plus the Phoenix code requires 2" for showers and I have a 2" p-trap but 1 1/2" drain pipe to the p-trap. The p-trap has a reducer that won't come off either.
I delaying progress now until my permits go through.

Copper pipe glue

I'm ready to move my copper water lines.
Question: Is the 2-part copper epoxy glue at HD adequate for my application?
I've used it to build fountains, and it seems really strong (I had to heat it once to dismantle it, and it still didn't want to come apart).
I don't mind paying a plumber to come in and sweat the joints (I'm not good at that) but if it works and lasts a long time, I can finish the water pipes.

Thanks.
Mark

Re the drain centering...

You want 1/4" per foot slope on the longest length. So on a 30x60 inch opening, if your drain was near one end, say 10" from the end, you'd need about 1+ inch slope. In the 10" from the short end, you still have to drop 1+", which is alot. 1+" over 50" isn't much, but the same over 10" is. You want the bottom edge of all of your tile all the way around at the same elevation or it looks funky. So you'll have that 1+" of drop from the short sides, as well. My unprofessional opinion. That's why many showers are square.

Note, had you considered using the www.schluter.com Kerdi shower kit for tiling? They have a preformed pan (you tile over it) specifically made to replace a standard 30x60" tub. Because it is preformed, and the way it goes together, they get away with slightly less slope. Makes a bulletproof tiled shower...check it out. You get to use drywall for the walls, too. The Kerdi membrane is waterproof and has been in use in Europe for decades with great results.