Move a shower drain about 6 inches

I have a roughed in shower drain in a concrete slab that is set 18" away from both walls but my shower base of choice is 12". The base already has about 3" of clearance under it so can connect it with 2 90's for that short distance? Or does anyone know of a neo-angle base with the drain 18" out?

You don't want those angles in the drain, you'd never be able to clean it if it needed it and the trap should be directly below, not offset. To keep the required slope so it would drain properly, it could raise your height too far to install the drain assembly. Probably not a problem over 6", but it would depend.

Are you planning on tiling the walls? If so, check out www.johnbridge.com. While there are some decent pre-made shower pans, it isn't really all that hard to make a custom, traditional one. You must pay attention to detail, but the actual work is pretty straighforward. There are some other techniques that work well, too: Wedi and Kerdi come to mind. With Kerdi, you can make a custom mudbed and then do the waterproofing if you cannot use their pre-made forms. Wedi parts can be cut, and one might fit what you want to do. Kerdi is easier to find, but Wedi is available if you look.

You could also consider having a cultured marble base made to your 18" x 18" drain location.

shower

I believe there are a couple of companies which make a Neo-Angle base with an 18" measurement, but if you cannot find on, and since there is NOT enough room under the base, either moving the drain or using a 36" two curb base with 2 glass walls may be an option, depending on how the door would work.

busting concrete

Thanks for the info everyone. I found a few bases by Kohler that are close but not quite right. So if I do decide to move the drain, and I cut the concrete, can I do 45's under the slab to position the new pipe? I thought I read a similar example on this forum.

drain

It is ALWAYS better to move the trap than to offset the riser.

My fear is that the arm of the trap heads off in a direction other than the direction I need to move. So I'd need to insert some unknown angle into the arm. Assuming I was lucky enough to have that angle availabe, is that acceptable?

Consider this...the shorter the path to the trap, the less surface area in the pipe can smell when it gets coated with hair, body oil, soap scum, skin particles, etc. There's a reason the trap is placed right under the drain. Will it work? Yes. With angles in there is is more likely to get clogged? Yes. Will it be harder to clean out if it ever does get clogged? Yes.