I've installed several of the Kohler CI shower receptors. For clarity...the bottom edge of the tile isn't supposed to be 5/8" above the top of the receptor. The tile backer board is held a minimum of 5/8" above the top of the receptor. The tile itself can go lower. Whenever the tiles get kicked out like that, it's a sign that your wall studs needed to be furred out before the backer board got installed over the studs. Or as Bill wrote, another layer of cement board could have been put over the first. Your wall simply needed to be "thicker." I furr the studs by ripping strips off the edge of a 2x4 to whatever thickness is needed. Usually 3/16" give or take. It depends on the tolerances used in the initial wall framing. Those strips go right on the exposed edges of the studs to furr the wall out a bit. Then the backer board gets installed. Then the tile get set with no interference from the radius of the receptor's flange. Look at the diagrams at the top of page 8 in this pdf, you can see the furring strips, or "shims" between the wall studs and the tile backer board: http://www.us.kohler.com/webassets/kpna/catalog/pdf/en/1009404_2.pdf

Sounds like you will have the sink cabinet replaced, right, that's great - you will be happier in the long run! Just want to ask - what is the Brand name (and the color of white) of these beautiful cabinets? Looks like a style that will fit very nicely in our new Old House! May I also ask, what have you selected for your Counter Top, Floor, Back Splash, Sink, Frig. and Range? And what is the size of your Kitchen and the Island? I also used glass doors over the sink in my last house - really makes the space open up - used the antique glass, looked lovely. Wish we were almost finished - Thank you so much for sharing, roseofblue

The IRC, if applicable, is not specific about the definition of "exposed ground". I interpret it to mean any vapor permeable surface on the ground but it doesn't say that and a slab might retard vapor somewhat. But the code also requires an unvented crawl space to have mechanical ventilation and an 18x24 access opening, so the builder owes you that in any case. The inspector owes you an explanation for why the work passed inspection not that he owes you any more than that and you shouldn't put him on the spot more than necessary to motivate him to tell the contractor he has violated the building code. the usual problem with those situations is who the inspector's relatives and friends are. I have shown some of the relevant code requirements in bold below. Italics means a term is defined elsewhere in the code. 2012 International Residential Code: SECTION R317 PROTECTION OF WOOD AND WOOD BASED PRODUCTS AGAINST DECAY R317.1 Location required. Protection of wood and wood based products from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative-treated in accordance with AWPA U1 for the species, product, preservative and end use. Preservatives shall be listed in Section 4 of AWPA U1. 1. Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation. 2. All wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground. 3. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier 4. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 1/2 inch (12.7 mm) on tops, sides and ends. 5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground or less than 2 inches (51 mm) measured vertically from concrete steps, porch slabs, patio slabs, and similar horizontal surfaces exposed to the weather. 6. Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier. 7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members. ___________________ R408.3 Unvented crawl space. Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where: 1. Exposed earth is covered with a continuous Class I vapor retarder. Joints of the vapor retarder shall overlap by 6 inches (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall; and 2. One of the following is provided for the under-floor space: 2.1. Continuously operated mechanical exhaust ventilation at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7m2) of crawlspace floor area, including an air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2.9 2.2. Conditioned air supply sized to deliver at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7 m2) of under-floor area, including a return air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2.9 2.3. Plenum in existing structures complying with Section M1601.5, if under-floor space is used as a plenum. R408.4 Access. Access shall be provided to all under-floor spaces. Access openings through the floor shall be a minimum of 18 inches by 24 inches (457 mm by 610 mm). Openings through a perimeter wall shall be not less than 16 inches by 24 inches (407 mm by 610 mm). When any portion of the through-wall access is below grade, an areaway not less than 16 inches by 24 inches (407 mm by 610 mm) shall be provided. The bottom of the areaway shall be below the threshold of the access opening. Through wall access openings shall not be located under a door to the residence. See Section M1305.1.4 for access requirements where mechanical equipment is located under floors. R408.5 Removal of debris.The under-floor grade shall be cleaned of all vegetation and organic material. All wood forms used for placing concrete shall be removed before a building is occupied or used for any purpose. All construction materials shall be removed before a building is occupied or used for any purpose.

To *check is ability, go ahead and ask him what your subfloor is rated as when it comes to deflection rating. And then ask what the TILES require as a deflection rating. And then ask how thick your CURRENT subfloor (plywood only) is and how many layers it consists of. If he looks at you as if you have TWO HEADS, then you know you are in for a LONG bout of 'shoulda, woulda, coulda'. Without the THICKNESS of the plywood subfloor, without the AMOUNT OF LAYERS and without knowing the joist measurements (aka joist on centre = "joc" measurement), there is NO WAY to know if you have ENOUGH support to handle a new tile floor. As I pointed out earlier, it is entirely possible the old chipboard was ADDING to the stiffness of your subfloor. The cement board is NOT adding to the stiffness. It is only to provide a 'nice' smooth flat surface to add tile to. It does NOTHING to help your deflection rating. Nothing!