What's the minimum amount of rise I can expect our of self-leveling mortar?

I'm working on a boathroom that sits on the slab of my house; I'm replacing the pan of my stall shower at the moment. The new pan has a tight structural grid on the bottom so it's not forgiving of irregularities in the foundation. My thought was to pour self-leveling compound over the 36" by 36" spot where the pan will sit. I don't want to raise it too much, though, because the drain pipe is supposed to be flush with the surface. It's already flush. I figured I'll be ok if it raises it no more than 1/4".

Sorry if this seems like a silly question - I've never worked with the stuff before so I haven't seen it in action.

Any other suggestions? I figure any irregularity is ging to cause the base to flex more and thus shorten the lifespan. Is using self-level mortar easier than trying to chisle down the high part? The part that seems to be high looks like a product that was added on top of the slab, not simply a result of a poor leveling job when the slab was poured.

-Chris

 

I would suggest setting the base in fresh concrete or mortar rather than trying to get the floor to match the underside of the pan. That's how we do fiberglass/acrylic tubs and showers in my area. Just mix up a bag or two, place it where the pan will go and jiggle the base into position.