I have taken out a bathtub and am putting in a tile shower. To put the drain in the middle of the shower I need to extend the pipe out laterally about 20". I am afraid that doing that will cause backup or clogging. Is there really any problem with keeping the drain towards one end of the shower?

If you're hand-tiling the base of the shower area then there's no problem making it drain to the pre-existing place.

... but the truth is also: a 20" sloped horizontal on the first part of the drain... before it gets to the trap... is not a problem either.

Either way the real work will be doing the sloping of the floor by hand - which I assume you already have taken into account.

Hey thanks for the help. Yeah the shower tiling will be pretty tough but I am pretty handy at tiling, my problems have all been with plumbing. I guess if there is no problem with a 20" slope I am going to stick with putting it in the middle. However I have one question about what you had said. I assumed the trap should go directly under the drain and then slope it to the wall. Are you saying I should slope from the drain and then put the trap 20" away from the drain? Appreciate your expertise.

If you're going with the drain in the middle - either way is equally effective:
Adding the 20" line and connecting where the trap is now, or do the trap right under the drain if you have room.

I don't see a reason to prefer either. Whatever's easiest.

... but if you're not doing the job today, wait a bit for speedball's take on it too.

End drains are common and acceptable in tiled showers. How ever, what may not do is create a "S" trap which is what you'll be doing if you leave the trap where it is and come off the drain with a elbo, a 20" pipe and another elbo to connect to the trap.
I would leave the trap alone and make my drain on the end but if you're dead set on having it in the center you must bust up the cement and position the trap under where you wish the drain to set. Good luck, tom

Thanks for adding that, speedball1.http://www.jackson8.com/images/amhd/thumb.gif

Heed speedball's advice, cwashington - you can't go wrong.