Hello everyone, I'm remodeling a sunken shower here in Florida. The house is on a concrete slab, and the shower is sunken into the slab. The dimensions are 70" L x 35" W x 10" D (17 SQ FT). I'm thinking of just extending the drain and pouring concrete with no rebar. Here's a picture of the shower; https://goo.gl/photos/b5nJJhofuw2mzSQ26 Thoughts?

Buy seasoned used lumber for joists and have tile installer bridge between different floors with urathane caulk. Tape is applied bridging gap then urathane applied over tape. The idea is tape come's loose to slide to and fro while urathane adheare's only to sides of tile and stretche's x contract's with movements. Urathane come's in colors close enough to basic tile colors. To view example of urathane,look for parking garage expansion joints,filled gap between commercial buildings and sidewalk,brick/stone wall expansion joints and other masonary work. Even if the low room were filled with concrete the joint will have uneven movement and never be fit for normal tile. Think about required expansion joints in concrete mentioned above. Many wood floors snap togeather and float,have a look at those.

Thank you for your response, the ceiling height in the basement would be to level out with rest of basement. No, I would not want to go lower. The sunken living room floor on inside has joist hangers already, this is on the main house middle beam. I do NOT have my floor open yet but here are pictures I found online that would be very similar to mine. the hangers on inside with wall dividing rooms right on the load bearing beam. The other picture would be the way on outside of wall with joist sitting on sill plate. My thought was that the living room floor that I need raised has no bearing on the rest of the structural walls. With in this living room I would be able to remove finish floor, sub floor to see all of floor joist.

Well, presuming you were going to cover everything with new flooring or carpet, you could put appropriate size framing in the hole, attach the perimeter of it to the existing concrete, and cover it with something solid, like tongue-in-groove 1-1/8" plywood. I had something similar done on a smaller scale when I remodeled my master bath and removed a large sunken tub. The contractor framed out the hole and screwed down underlayment to bring it up to the level of the rest of the floor. Worked fine....