You bring up an excellent point about two layers of the RedGuard. I hadn't thought about the fact that we will be trapping whatever moisture exists between those two layers of RedGuard. I'll discuss this with my tile setter. With respect to heating mats in the shower I have thought about this and believe this to be a low/no risk situation. The companies that sell the heating mats that are installable in showers don't want liability either, and I feel confident that their products have been tested. I looked for any customer complaints, or lawsuits with respect to radiant heat in showers and couldn't find any. With our litigous society I'm sure someone would have sued if there was a problem so...I'm going for it.

kichen4us, All I can suggest is be firm with him, and if he doesnt repair or replace the job to your satisfaction, you may have civil legal recourse. It isnt the easiest nor nicest route to go, but sometimes it's really the only route. He screwed up a job and isnt making good on it. So what else can you do accept let him rip you off or force the matter legally? Our industry is plagued with uneducated installers, and for whatever reasons, whether that be ego, pride, or a lack of knowing any better, they give us a bad name daily. Consumers need to step up and require that they be held accountable. This is the only way things will ever change with the uneducated hacks. This also helps to prevent future consumers from enduring the same experiences and can have ripple affects in either: the isntaller no longer doing this type of work, or pressure them into becoming more educated if they really care. In the end it's up to you what you do about it, if anything. I hope you havent paid him or cancelled the payment until he fixes it since he obviously doesnt know enough to be doing this in the first place. Sorry If I seem harsh, but I am a firm believer in taking responsibility for your actions and installation education. It doesnt matter WHY its done inproperly, and if mistakes are made you make good on them or pay someone who can in repairs or replacements. Ok I am off the soapbox now. Here is how I would have laid out a diagonal kitchen/combo room with a hallway. Since I dont know the shape, size, and layout of your area, I created one below. Here is the way we educate all employees to approach every tile job whether that be rectified porcelain, ceramic tile, or stone tiles. Lay out the tiles on the floor with the customer requested joint sizes into a managable square (in this case lets say 3, 12"x12" tiles, with in your case, 3/16" joints. Now we have 9 tiles on the floor forming a perfect square with the joint sizes set all equal. We then measire that squares dimension and mark this on a piece of paper for reference. This we keep consistent throughout the installation process and never deviate from it, so if there is ever any error, that error only resides in that one square containing 9 tile and is easily fixed. As illustrated, this one single block of the installation grid we will place on the floor and re-use over and over again, and we have a measurement of 36&3/8" tile to tile, and 36&9/16" tile to joint, so we write those both down. Next, we want to create a temporary line parallel with the longest wall, preferrably an exterior wall. We get this by measuring into the room on each end of that wall and striking a chalk-line connecting those 2 points. Next we strike a true perpendicular temporary line down the center of the hallway and double and triple check it for being truely square using the Pythagorean Theorem and number triples for proof of a true right triangle. (e.g. 3'squared x 4'squared = 5'squared , or A squared plus B squared equals C squared, meaning, For any right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides .. there are many pythagorean triples number sets that will work for this ... here is a handy generator). The reason I am going into the mathmatics of obtaining the perpendiculars, is that without the lines being absolutely perpendicular, the tile isntall can be off, and this is expecially important with rectified porcelain because their thin joints allow very little room for error and tile positioning withing the gridswe are going to construct. Simply laying a carpenters square on the floor, hoping its square, and striking a long line off of that very small reference is not a proper way to layout a ceramic install grid system and a perpendicular. MEASURING and using geometry is the correct way ... and it's absolute and accurate everytime. The purpose of these temporary perpendicular lines perform a few function. First, we use them to measure the other walls off of to ensure the areas are square to the lines which are square and perpendicular to the main exterior wall we used to make them, like the hallway and wing walls in the kitchen. If they are not square and perpendicular within reason, then we can slightly adjust the line sets to achieve this while keeping them perpendicular to each other. Next we want to create the first of two main diagonal control lines on a true 45 degree angle. Since we have proven that our main control lines are true perpendiculars, we can do this very easily by simply measuring an equal distance off the intersection of the temporary lines (any 2 next to each other). So if we measure exactly 10 feet in two directions off the intersection, make a mark, then connect those points, this gives us our diagonal ... a true 45 degree angle from each temporary line. We then measure back the distance to the intersection, transfer that distance on each end of our new line, then place that diagonal on our intrsection, which becomes our first main control line. We want to pick a long open spot on the floor that goes between any obstacles, like cabinets and islands so its easier to measure around them for our grid system ... a place where we can place a main control line. This line may need adjusted a little later after we figue for cut size equalization and tile placement layout. THis ensures absolutely that our grid system and all lines are perfectly square and parrallel around any obstruction like cabinetry and islands. Using the previously mentioned set of Pythagorean triple numbers we strike a perpendicular control line both on diagonals, then create a perpendicular like we did previously. Ok so now we have our 2 control lines (in red in the below illustration) that are truely perpendicular to each other, so now we dry lay outa few tiles to ensure these staring control lines are exactly where we want them in terms of tile start oints and cut sizes. If they arent where we want them we simply measure off of them and move them as needed maintaining the perpendiculars and using the new lines. It is a simply matter of measuring and laying out tiles dry, then moving the lines evenly as needed to get the correct cut size at each wall, while ensuring the high presentation area of the hallways remains on-center (as illustrated). Next we have to mark and snap chalk lines for every block to grid out the installation area using our information we wrote down from the first illustration for the tile block. We use either the tile to joint or tile to tile measurement depending on the installation justification. (e.g. all perimeter cut lines I like to set the grid to the tile edge to do the cuts first, then I use the tile to joint measurements in the open field. This allows an easier installtion for the most part, because you can be set up for all cuts, then come in and do the field, but some installers like to do cuts as they install). here is a illustration: the light blue/aqua lines represent individual tiles and they are for reference only and not meant to be individually marked on the subfloor. After the grids are all in place, the installer needs to measure random grids in separate sections of the installation corner to corner. If theya re all within 1/16" then the grid system is square and ready to install. If not, there there is a problem somewhere throwing it out of alignment. You said the isntaller stared in the hallway. If he did this without gridding it out, then I would have to say its improper and is probably why nothing is ligning up right and he has to move tiles to shuck and jive the isntall to make up for the errors. This is almost impossible with unltra thin joints with rectified porcelain because there is no room for adjustment. As to the high tiles, a good tile man will have a masons level or something similar with them laying on top of the tiles as they install them to prevent lippage. If there is any lippage, the add or remove thinset as needed for flush heigh from tile to tile. Also, I need to add that sometimes a substrate or subfloor might be wavy and this is something that is the installers responsibility to CHECK and address prior to the install if there are any issues with height and waviness. In conclusion, in my opinion, the only proper way to do a sizable area is the grid system I have shown. When the grid is completed and marked correctly, ANY problems will be within one single grid and is easily fixable. This is basically along the same lines as the carpenters creed ... measure twice or three times ... cut and isntall once. here is a copy of the full size illustration if you want it:

Hi Nancy-- He did what's called "spotting" the tile. IOW, instead of spreading the wall and just slapping the tile up, he just put spots of thinset on the back of the tiles. The thing that gets me is this is usually used to make sure all the tiles sit nice and flat to each other and the finished wall stays nice and plumb, in spite of what the subsurface of the wall may be doing. Just about any time I set marble on vertical surfaces, I'll "spot" them. A backsplash, though-- I don't think I'd waste the time. For that small a space, it's usually not necessary. One way or the other, so long as he gets it flat, I wouldn't worry about it. You might ask him to fill in any empty corners you can see, but beyond that, don't worry about it.

Botticino is great stone-its quite dense. Therefore even honed it won't take in much sealer. Not sure what you mean by unhoned-polished? The carrara is another story as it can be very porous. White marbles can also have ferrous minerals in their composition. Placed in wet environments they can oxidize or rust. Sometimes white marbles will exhibit yellow,brown or orange stains. White Carrara when it gets wet looks very grey. It is one of the marbles I think should be sealed in a shower stall. I am not a fan of sealing all marbles in a shower stall because I think in some cases water getting below the stone will take longer to evaporate because of the sealer. To answer your questions . How often to seal -it isn't the sealer that will protect your stone as you have been lead to believe . It is the installation along with the proper specification of material. Natural stone requires in most cases impregnating sealers however some slates and other products can be top coated . Topcoats are acrylics and waxes which will need to be maintained and will fail often in shower stalls. The performance of an impregnating sealer is to temporarily inhibit the intrusion of a staining agent. When you think about that -how many things in the shower can stain the stone. The culprit is usually water and not from above the stone but from below it. This is why caulking all the change of plane joints is so important. Along with the proper slope to the drain and the proper construction of the shower pan. Even then there can be some issues. Polished marbles in shower stalls will over time become uniformly honed by steam. Something that isn't talked about often. I hope this helps.