Much depends on the reason for the crack, and if the crack is active or if it's old and has stabilized. ie, no more movement. If the crack is active, it's an "all bets off" type of scenario. There's no sense in tiling over an actively moving slab. I'd need to know why it's moving. Expansive clay underneath? Water issues? Poorly compacted subsoil that has settled and thus the slab has sunken in? There are myriad reasons. Not all cracks are problematic. Large expanses of concrete can show shrinkage cracks. They are simply a part of the curing process. Shrinkage cracks will never move, they really aren't an issue. Some structural cracks are done. They've moved. They've settled. They've stabilized. They'll never move again. So not all structural cracks are an issue. It's simply actively moving cracks that you need to be wary of. SInce you've already made patch repairs to the slab, I'm guessing that the existing cracks are not active. Were they active I'd have recommended digging out the broken concrete. excavating down, filling and compacting a new base, then repouring a new slab. For your case with the cracks being inactive, I would put a crack isolation membrane down. That'll serve two purposes: 1) It'll isolate the cracked slab from your mud bed. 2) It can act as a moisture barrier, preventing moisture in the earth below the slab from wicking up through the slab and into your new mud bed. A crack isolation membrane I use is Nobel CIS. You can then put your mud base on top of the CI membrane and work up from there. I'd recommend Hydroban with that. Hydroban is a water proof barrier but not a vapor barrier, so it'll work well with the CIS which is a waterproof and vaporproof barrier. The good news? Sort of? If you use Nobel CIS (or use an equivalent product) over the entire bathroom floor slab, then you can put the sloped mud (or preformed shower tray) over the shower portion of the floor and then simply tile over the CIS on the remainder of the floor. Do understand it's not the only way. There are other products you can use. Does that make sense?

To the OP, kgsd: Yes, drains can be offset form the center of the floor. It happens all the time, especially in larger walk-in showers. A couple of considerations...with offset drains it's best to keep the bottom edge of the bottom course of wall tile at the same height all the way around the shower. That means that the perimeter height of your sloped floor pan, where it meets the wall, will be the same elevation al around the shower. Code requires a couple of things; that the minimum slope of the shower floor be at least 1/4" per foot, that the maximum slope be 1/2" per foot, and that the height of the curb needs to be 2" above the height of the drain. If your drain is centered in the existing 36" square pan, you have 18" from drain to wall. Add 24" to one side for a 3' by 5' shower and you'll have distances of 18", 18", 18", and 42". Using 1/4" slope per foot on the long run will give you a needed rise of 7/8". Taking that 7/8" elevation and applying it to the three short runs will give you a slope slightly steeper than 1/2" per foot. To fans of trough drains. They are easy to construct, I've done one "old school" and a couple using Kerdi. Made the troughs myself when setting the dry pack. I also made one out of copper, bent on a brake and soldered the corners. Drain the floor to the trough, then drain the floor of the trough to the drain. Factory trough drains are available, but expensive, since most every shower I've done is a one-off size, it's much easier to just make my own. Plus I know it'll work. Check with your building department. The first one I did the inspector wanted me to tear it out. After I educated him, he allowed it. Mongo the insomniac

Thank you everyone for your responses! I love the idea of practicing! Also, thank you for the links. I want to learn as much as I can about building a shower. If nothing else, at least I will know how it's supposed to be done, so that if someone else does it, I know it's done right. I really want to try to do it myself. So, Lazarususa, you do like the Quick-Pitch. I saw where someone else really liked using them too. I think I need to buy a book with step-by-step deatails of the process. I did read that the tiles are going to need to be flush with the drain when they are laid. The plumber installed the new copper pipes for my body sprays and then told me that he went ahead and put in the new liner and drain. He did that without a pre-slope being done. What should I do now? I saw a product called Proslope that will cut-to-fit and fit around the drain. Can I use that and then lay the liner back down on top of it? Or do I need to remove the liner and drain and start over? I didn't know the plumber was going to install that. The floor underneath it is level and then just drops off around the drain. This shower wasn't done right in the first place by the builder. When it was torn out, it became evident that the tile was set right on top of sheetrock. It will be wonderful to have a shower in my master bath again! I am doing one thing at a time. I also have a separate tub in the master bath. But it's just a regular porcelin tub on a wooden platform. I would like to remove it and add a jetted tub after I tackle the shower issue. :)

417.5 Shower floors or receptors. Floor surfaces shall be constructed of impervious, noncorrosive, nonabsorbent and waterproof materials. 417.5.1 Support. Floors or receptors under shower compartments shall be laid on, and supported by, a smooth and structurally sound base. 417.5.2 Shower lining. Floors under shower compartments, except where prefabricated receptors have been provided, shall be lined and made water tight utilizing material complying with Sections 417.5.2.1 through 417.5.2.4. Such liners shall turn up on all sides at least 2 inches (51 mm) above the finished threshold level. Liners shall be recessed and fastened to an approved backing so as not to occupy the space required for wall covering, and shall not be nailed or perforated at any point less than 1 inch (25 mm) above the finished threshold. Liners shall be pitched one-fourth unit vertical in 12 units horizontal (2-percent slope) and shall be sloped toward the fixture drains and be securely fastened to the waste outlet at the seepage entrance, making a water-tight joint between the liner and the outlet. 417.5.2.1 PVC sheets. Plasticized polyvinyl chloride (PVC) sheets shall be a minimum of 0.040 inch (1.02 mm) thick, and shall meet the requirements of ASTM D 4551. Sheets shall be joined by solvent welding in accordance with the manufacturer’s installation instructions. 417.5.2.2 Chlorinated polyethylene (CPE) sheets. Nonplasticized chlorinated polyethylene sheet shall be a minimum 0.040 inch (1.02 mm) thick, and shall meet the requirements of ASTM D 4068. The liner shall be joined in accordance with the manufacturer’s installation instructions. 417.5.2.3 Sheet lead. Sheet lead shall not weigh less than 4 pounds per square foot (19.5 kg/m2) coated with an asphalt paint or other approved coating. The lead sheet shall be insulated from conducting substances other than the connecting drain by 15-pound (6.80 kg) asphalt felt or its equivalent. Sheet lead shall be joined by burning. 417.5.2.4 Sheet copper. Sheet copper shall conform to ASTM B 152 and shall not weigh less than 12 ounces per square foot (3.7 kg/m2). The copper sheet shall be insulated from conducting substances other than the connecting drain by 15-pound (6.80 kg) asphalt felt or its equivalent. Sheet copper shall be joined by brazing or soldering. SECTION P2709 SHOWER RECEPTORS P2709.1 Construction. Where a shower receptor has a finished curb threshold, it shall be not less than 1 inch (25 mm) below the sides and back of the receptor. The curb shall be not less than 2 inches (51 mm) and not more than 9 inches (229 mm) deep when measured from the top of the curb to the top of the drain. The finished floor shall slope uniformly toward the drain not less than 1/4 unit vertical in 12 units horizontal (2-percent slope) nor more than 1/2 unit vertical per 12 units horizontal (4-percent slope) and floor drains shall be flanged to provide a water-tight joint in the floor. P2709.2 Lining required. The adjoining walls and floor framing enclosing on-site built-up shower receptors shall be lined with one of the following materials: Sheet lead; Sheet copper; Plastic liner material that complies with ASTM D 4068 or ASTM D 4551; Hot mopping in accordance with Section P2709.2.3; or Sheet-applied load-bearing, bonded waterproof membranes that comply with ANSI A118.10. The lining material shall extend not less than 2 inches (51 mm) beyond or around the rough jambs and not less than 2 inches (51 mm) above finished thresholds. Sheet-applied load bearing, bonded waterproof membranes shall be applied in accordance with the manufacturer’s instructions. P2709.2.1 PVC sheets. Plasticized polyvinyl chloride (PVC) sheet shall meet the requirements of ASTM D 4551. Sheets shall be joined by solvent welding in accordance with the manufacturer’s instructions. P2709.2.2 Chlorinated polyethylene (CPE) sheets. Nonplasticized chlorinated polyethylene sheet shall meet the requirements of ASTM D 4068. The liner shall be joined in accordance with the manufacturer’s instructions. P2709.2.3 Hot-mopping. Shower receptors lined by hot mopping shall be built-up with not less than three layers of standard grade Type 15 asphalt-impregnated roofing felt. The bottom layer shall be fitted to the formed subbase and each succeeding layer thoroughly hot-mopped to that below. All corners shall be carefully fitted and shall be made strong and water tight by folding or lapping, and each corner shall be reinforced with suitable webbing hot-mopped in place. All folds, laps and reinforcing webbing shall extend not less than 4 inches (102 mm) in all directions from the corner and all webbing shall be of approved type and mesh, producing a tensile strength of not less than 50 pounds per inch (893 kg/m) in either direction. P2709.2.4 Liquid-type, trowel-applied, load-bearing, bonded waterproof materials. Liquid-type, trowel-applied, load-bearing, bonded waterproof materials shall meet the requirements of ANSI A118.10 and shall be applied in accordance with the manufacturer’s instructions. P2709.3 Installation. Lining materials shall be sloped one-fourth unit vertical in 12 units horizontal (2-percent slope) to weep holes in the subdrain by means of a smooth, solidly formed subbase, shall be properly recessed and fastened to approved backing so as not to occupy the space required for the wall covering, and shall not be nailed or perforated at any point less than 1 inch (25.4 mm) above the finished threshold. P2709.3.1 Materials. Lead and copper linings shall be insulated from conducting substances other than the connecting drain by 15-pound (6.80 kg) asphalt felt or its equivalent. Sheet lead liners shall weigh not less than 4 pounds per square foot (19.5 kg/m2). Sheet copper liners shall weigh not less than 12 ounces per square foot (3.7 kg/m2). Joints in lead and copper pans or liners shall be burned or silver brazed, respectively. Joints in plastic liner materials shall be jointed per the manufacturer’s instructions. P2709.4 Receptor drains. An approved flanged drain shall be installed with shower subpans or linings. The flange shall be placed flush with the subbase and be equipped with a clamping ring or other device to make a water-tight connection between the lining and the drain. The flange shall have weep holes into the drain.