This is a common request but can be difficult for a tile setter to embrace. The larger the tile the more difficult is the ability to lay a flat floor that is free of "lippage'"; an occurrence more common and noticeable with large and larger ceramic tiles. Tiles are made by man in a multitude of molds that are made in close but variable tolerances. As tile sizing varies, smaller grout joints become more difficult for the installer and customer complaints are frequent. Customers wrongly assume that the larger the tile the quicker and easier it should be to install them. The opposite is true and the labor to install 20 inch tiles can be double, take twice as long to install. The smaller the joint the more difficult the installation can become. These large format tiles have to be leveled more carefully and individually, to avoid or at least minimize "lippage". My TAVY "Tile Puck" is growing in popularity to control and minimize lippage. Smart installers would rather see install times shrink rather than lengthen. Quality can be maintained, and install times can become more realistic when using the right tools for the job. Grout joints for large format tiles might not be practical under 1/8". A more perfectly crafted tile might be installed by a tile "artisan" with the aid of my 3/32" Tavy Tile Spacer (their purple in color). Weight is not an issue on "legal" floors, walls are not a problem because the weight is "stacked". Ceilings on the other hand could be dangerous. Try to butt these tiles and you may regret it. Also remember that these larger tiles are heavier only because of their size. 4, 12 inch porcelain tiles held in one hand might weigh just slightly less only because of the 4 grout joints. These larger format tiles MUST be back buttered and then combed with a 3/16" V-notched trowel and a 1/2" x 1/2" x 1/2" trowel Must be used on the floors. The use of Medium Bed mortar mixes is prudent. "TIRTGIM" Armen Tavy

A simple bath in diluted household bleach can work wonders. Protect adjacent surfaces and clothing from splatter. "Aqua Mix" and "Tile Guard" are two brands that have good tile grout cleaners that whiten. We also have grout paints that are fairly easy to apply and will seal the grout for easier cleaning next time around. They are available in the tile isle of big box stores or at legitimate tile retailers. "TIRTGIM" Armen Tavy

You seem to be getting in deeper and deeper. All you're doing is staining the film that originally bonded to the surface of the tiles. This is the surface you have to get down to and remove. The only thing that comes to mind right now is a gel type paint remover. Coat it on, let it stay for as long as the instructions say, and then see if it resolves your problem. There’s just so much I can do from a distance without personally viewing the problem. Acetone is not a solvent for Latex based products.  If all else fails to remove the film try a very small amount of "Lacquer Thinner" but be careful, because it's extremely volatile. Sorry, Armen Tavy

Grout release is effective to prevent grout from penetrating into a porous surface or from getting into small crevices. If you coat these tiles you say have small holes where grout should go it might prevent the grout from sticking/filling the intended places. I would get an extra tile and experiment rather than wait until the tiles are installed. The best way to tile over the existing marble would be to use my TAVY Thin-Skin Tile Underlayment. www.tavytools.com , for sources. It does work over marble and anything else you can think of except carpeting and upholstery. If you have cake decorating experience and patience you could use a grout bag. Excess grout is washed off with a Tile Hydra Sponge; they are big, thick and yellow. . You might also use a 2, 3 or 4" throw away paint brush for touch up washing. If the bristles are too soft to be effective, trim/shorten them with a pair of scissors. “TIRTGIM” Armen Tavy

There is much information that you will need to complete a tiling project like this and I have written often about the Do's and Don'ts in the last 6 months about it on this forum. Try reviewing older posts and you will learn much. In the meantime, it doesn't matter how large or how heavy the tiles are. As long as you can lift them, your bathroom won't care. I have 20" x 20" "Rectified Porcelain" tiles in a very small bathroom including the floors, the walls and tub surround and if you review older posts you will read that I have said that my installation is "Simply Marvelous" as do all who see it. Modified Thin-Set Mortar is your only option when installing large format tiles. Write again if you need more detailed help. "TIRTGIM" Armen Tavy

You're supposed to close the window when it's snowing outside (ha, ha ) or someone shook a talcum powder container and blew it around for a joke, or it could be dry wall dust from someone doing some remodel work in the bathroom or in close proximety to the room. Other than any of the latter scenarios, you would have to review all the things you may have done differently in the last few days or just before you noticed the white powder. Gather some on your finger tips and give it a light sniff. If it's talcum powder, it will have a pleasant refreshing odor. If it's drywall dust it wont have any noticable odor at all. That's the best I can do with what little information you have given me. It's a mystery, but all mysteries have a logical answer. Armen Tavy

I'm afraid not however, you can tile over tile using my TAVY Thin-Skin www.tavytools.com for sources. You will need to use a tile that has "Mud Trim" available so you can "return the tile" to the wall. This tile trim has a rounded overlap edge, and the code number for 4 1/4" wall tiles is A-4402. Check at Lowe's or any other legitamate tile store in your town/city.

Instructions like this are always "hypothetical" and not meant to be referenced as exact measurements.  Most tiles manufactured today are not exactly the size marked on the box. You're actually "Charged for the open air in the grout joint". A twelve inch tile could/might measure 11 3/4 to 11/7/8" of an inch. Rare is the case that they would be exactly 12 inches. Buy my "TAVY Tile Spacers" in a size of your choice and place two "upside down", one at each end of a tile and between two tiles and add a third tile in the a test row. Use a tape measure, but make sure the tip isn't bent because it was dropped, and place it against the right side of the first of three tiles on the floor in front of you and measure the distance including the width of one grout joint to the left side of the third tile in the row. Record this measurement (one tile plus one grout joint) on paper or in your memory and use it to make your grid pattern/s. However I'm not a fan of "Grid Patterning" when there is an easier way using my "TAVY Tile Spacers". My spacers have a flat disc in their center and they easily sit on tiles so you can visually see what your installation might look like; use two, one at each edge between two tiles. Lay a complete row of tiles across the width of the room and decide what the best layout is using full tiles only, (you would leave out partial tiles). Make a reference mark/s on the floor drawing two short lines between two tiles, these two lines will represent the grout joint and the location of a full tile, including one grout joint. Do the same across the length of the room and make similar grout reference lines. You have the ability now to determine what size the cut tile/s will be or better yet decide if you can have a full tile at the entrance of the bathroom, which always looks better. If you choose to install a marble threshold, make a mark on the floor to outline its location. This point, closest to the inside of the room, will be against the last tile in the room (include a grout joint). You're the one who has to decide what looks best. If all this starts to make sense to you and you want to use my suggestions, ask again for help and I will include additional information next time you write. You could try outlining all the tiles on the floor, remove each tile after you outline it. This will take a little extra time, but may be the way for a novice with little or no experience to do a decent installation. Nervous novices have the option to lay the entire foor, including cuts "dry", and then pick up a couple of rows of tile at a time to re-install them in the exact location with "Mortar". Repeat the process until the entire floor is tiled. Waiting for your reply for additional pointers. "TIRTGIM" Armen Tavy

What you're saying doesn't make any sense. If you had used the right materials this scenario would be impossible. If you would like more help you would have to go into detail from begining to end, including the brand and description of the grout you used and how you mixed it. If you per chance used a grout made by "Laticrete International" called "SpectroLock" which is a 2 part system, you didn't buy both parts of the grout system. As a matter of fact I'm betting the "farm" on this one. Am I right? "TIRTGIM" Armen Tavy

Depending on what your technique is for buttering and spreading, the minimum should be 1/4" and the max 3/8". The backsides of these tiles tend to have deep indentations and if you completely fill them while skim coating the entire tile, so you cannot see the body of the tiles, and then spread the mortar on the floor holding your trowel at about 60 degrees, and make nice neat "corn rows" of mortar which is required now. The "rows" should be horizontal, left to right; no swirls please. If you do all this correctly you should end up with a 3/8" mortar bed. Practice with one tile now if you can, to make sure. Remember the rules about deflection with this "load". Your floor must be at least 1 1/8" thick and it must have 2 layers/sheets (4 x 8) of wood panels, i.e. exterior glue plywood, or OSB. Since it’s not a good practice to tile directly over the wood, consider 1/4" or thicker (1/2") Cementitious Backerboard (CBU) as your 3rd layer to make up the difference you need. If this combination raises the floor to high, your other option is to use my TAVY Thin-Skin Underlayment instead of CBU over 2 layers of wood. The original first layer/sheet over the floor joists should have been 3/4" or minimum 5/8" and the second sheet 5/8" minimum (and stagger the joints) or whatever it takes to get to the height you need. My Thin-Skin only adds only 1/32 of an inch, once it's "skim Coated".  "TIRTGIM" Armen Tavy

The smoother the finish the slippery-err they get. You can even slip and slide on marble with wet feet. I have beautiful shiny 13" rectified tiles on one bath floor and 20" on another, but we have decorative floor mats out side the shower and in front of the basins. They look great and solve the problem. However, if you don't particularly like mats, we do have spray or paint on products you can apply. A product called "Slip Stop" is one. Once applied it goes to work and lasts a long time. Go on line for this and other similar brands that will come up when you "Google". "TIRTGIM" Armen Tavy

I wish you had asked before you jumped in. Mastics are water base and they emulsify back to a paste form when subjected to a "water bath/s". I told "RPINO" in the previous post, that he/she should take time to read older posts to become familiar about the "DOs and DON"Ts" of tile installing. If you also used the same product for the wall installation he may be calling you again. I hope you at least used Cement Backerboard on the walls and you protected the weep holes in the shower pan before you filled it with cement, because if you didn't, you might have to m____ out of state, unless your neighbor is very forgiving. Sorry! If you have to rebuild, I don't mind helping you salvage as much as possible. "TIRTGIM" (Tile It Right To Give It Might) Armen Tavy

The description "Waterproof Sheetrock" has to be very specific because there is one product that cannot be used anymore (Green Board) and many people have used it unsuspectingly and jobs have failed. "Dens Shield" by Georgia-Pacific is one product you can use, as long as you read and follow the directions to install it. Of course, Cementitious Backerboard, although heavier and a little harder to work with, is time proven for enough years to make it predictably perfect. I have no idea what you mean by "can ceramic tile be mounted", please explain. Ceramic tile can be installed in tub surrounds and showers as long as "Rules" are followed. If you don't know them, you ask as you have done, only you have to be more specific about explaining what you mean so I can understand what you are saying.  Please take the time to review older posts, it’s really educational, if you intend to be a homeowner that would like to install there own tile/s. "TIRTGIM" Armen Tavy"

You haven't said how big your kitchen floor is and how large you have decided to make your panels. One trick that can solve your issues is to "snap" all the small tiles into smaller pieces and use the pieces randomly placed inside the panels. You would use a pair of "tile nippers", not a saw, to create the irregular shaped pieces. There are many restaurants that have tried this with red quarry tiles and it looks pretty good. The sharp edges of the tile pieces would have to be "sanded" so they won't cut your feet should you walk on the floor barefoot. The larger areas between the irregular shapes are filled with grout however; you would try to minimize larger spaces by manipulating the irregular shapes so there is less space between them, much like a random stone walkway in a garden. It will take a lot of patience but your artistic abilities might kick in and you could end up having fun with the project. If some of the cut tiles are thinner than others in the "mix" just put a little extra (thick) mortar under them. I would maintain equal grout joints between the larger perimeter tiles. Let me know if this works for you. "TIRTGIM" Armen Tavy 

Sorry tileguy, I accidentally deleted your new question, but here is my answer anyway. If you would be kind enough to resend it, I will move my reply to the correct post number. Thanks.    

There aren’t any wood boards of any kind that can survive in an exterior environment exposed to "Mother Nature's Elements indefinitely. Exterior grade anything made from wood or wood particles usually refers to the glues and resins that hold sections, layers, or particles together. Pressure treated lumber is the only accepted product, but because it's very pricy is avoided because exterior sheathing receives a moisture/vapor barrier and is covered with other products that can withstand the ravages of Sun and Storm, so why waste money on Pressure Treated. Even pressure treated lumber will deteriorate in time, unless it's covered with a protective surface. In our trade we only use it in "possible" damp interior environments or when direct contact to a slab may be a concern, like a "shower curb" or a "plate" to build a tub deck or partitions on. I haven't heard yet whether new formula pressure treated plywood, that doesn't contain arsenic, can be used as a substrate for tile. !/2" Cement board is for walls and 1/4" is recommended for floors. Your concern about installing it with wet cement can be resolved by using wood glue cartridges in a caulking gun. You don't need the top of the line glues since the panels will be secured so well with fasteners. The mortar industry has convinced everyone to use mortar to install their cement boards (it increases their sales) and I refuse to be "bullied" into their reasoning. I say level the floor with patch and then install the boards with glue (there is a specific glue pattern) rather than rely on mortar, which also raises the height. I also question anyone’s ability to pass the maximum 1/4" per lineal ft out of plane allowance test successfully, when using mortar to install any cement board.  I'm not sure if we've resolved the issues with shipping to Canada as yet, but I will look into it tomorrow and report to you. Thank you for your positive comments. "TIRTGIM" Armen Tavy

K-3 aka Particle Board is probably the "Stiffest" wood board made today, however it's dramatically and adversely affected by "water". It doesn't delaminate or warp; it swells/expands and then disintegrates/collapses when it gets wet or stays wet for even a few short hours. A water leak, un-observed for a weekend in your absence, will literally destroy it. Having said that, if the area isn't in close proximity to a water source and the odds of it ever getting wet are pretty nil, it could be tiled over but it would have to have an additional floor beneath it. You would also have to avoid all Portland based cement products. Organic based mastics can be used to install ceramic tiles over K-3 but can't exceed 8" x 8" in size. Now we have to discuss the definition of a "legal" floor thickness that's "TCNA" approved. That number, because of "fractions" used in lumber measurements has been reduced to a minimum of 1 1/8". A single layer of 5/8" of "anything" directly over floor joists is not officially accepted as a substrate that can support a ceramic tile load without issues and failures in a very short time after installation. Unfortunately, we have literally thousands of installations installed yearly over a variety of single layer 3/4" wood substrates that do not qualify as a tileable substrate. This is a dilemma and as long as installers are "bullied" by builders and homeowners to install over these provided substrates, our Tile Industry is going to be unfairly criticized for allowing it to happen. DIYs who watch a variety of home improvement shows, that are giving bad examples of how a tile installation should be done, are being led down a "Road of Regret". I personally "Cringe" at what I see on these shows, and you know the ones they are without my mentioning their names. Hypothetically speaking, you're determined to tile over a single layer of K-3, it would have to tongue and grove and the joints would have to be glued with a sub-flooring adhesive. If these glued joints were near the center of a 16" on center span the tiles might/could still crack. Tiles might even crack if the joints were directly over a floor joist, I've witnessed it. This all leads to this professional's conclusion. Why spend hundreds or thousands of dollars on a floor that will most likely fail sometime in the near future instead of spending an insignificant amount up front now. Even if you were to install 1/2" cement backerboard over a K-3 subfloor and the K-3 subfloor got soaked and disintegrated anyone could conclude what would happen to the cement backerboard and the tile installation on it. I could write several thousand words on this subject but this is not the proper place or time. You could coat the K-3 with that rubberized membrane you mentioned, that’s painted on wet. Moisture from a leak in the perimeter or from below would be the only ways to compromise the integrity of K-3. Moisture from “wet” thin-set penetrating thru a cured waterproof membrane is literally impossible unless you made knife cuts in it. These specialty compounds are guaranteed by their manufacturers as a suitable substrate to tile over, however check the “fine print”.   After all this, would I advise tiling over a single layer of 5/8” thick K-3? The answer has to be No. “TIRTGIM” Armen Tavy                                                                                                        

The main criteria here is whether the inside corners of the cement backerboard had at least 1/8” air gap spacing and the/that air gap was filled with modified mortar, taped with alkali resistant cement board tape, and finish coated with more mortar. If the answer is Yes, I would use the same cement grout that was used in the rest of the installation. If the answer is No, then a flexible color matching caulk would be advisable. Where cement grout meets wood casings, jambs, etc. it has a tendency to shrink slightly. I would wait until that occurred and then fill any small “gaps” with flexible caulk but, “promise” me you will wash off all excess caulk and leave only enough to fill the “gap”. Many people tend to over caulk which is unsightly. “TIRTGIM” Armen Tavy

The Industry SAYS, 24 hours. Enjoy your warm floors. "TIRTGIM" Armen Tavy

Please take the time to scan older posts and replies for so much information pertaining to questions like yours as well as other advice that can help you with most tiling questions without even asking a question and waiting for an answer. In the meantime, "Lauan" is absolutely "Verboten" as an underlayment for any finished flooring, as determined by yours truly, and all our Industry Experts,………. with no exceptions. Many jobs have been installed over “Lauan” and for some unknown reason have survived, but the failures out weigh the successes, so you should avoid this product like the “Plague” and choose a variety of other Underlayments, many, including my own TAVY Thin-Skin”, are guaranteed to work if you read the directions and follow them. Please avoid using pre-mixed adhesives for floor tiles and choose a quality name brand Modified Mortar. The same applies to the Grout. I have favorites but hesitate to influence you and reject others that are probably as good. If you stay with name brands they all carry warranties for your piece of mind. Some Brand New Ones have claims that they are “stain proof”.  “TIRTGIM” Armen Tavy

Fantastic people come to this site and the only option is to give fantastic information in return. Rialto Tiles sold by Lowe's is an amazing tile and one of this moderator’s favorite to install. As a matter of fact 43 weeks out the year I take a 2 day trip somewhere in the country and speak at tile training seminars about the “DOs and DONTs” in tiling techniques and use these tiles in 12” and 16” formats in the hands on demonstrations. I also talk about my TAVY Thin-Skin Underlayment and I never forget to show the value of my TAVY Tile Puck which everyone should use to check for Lippage. Rialto tiles have larger depressions on the backside, that I liken to a Belgium Waffle, and these depressions must be back butter and filled flat just before installing on a Bed of Modified Thin-Set Mortar (Spectra Set is great). The clean bare substrate must be skim coated first and then troweled with a minimum 1/4" x 3/8" x 1/4" rectangular notched trowel held at 60 degrees while spreading. The 30 minute comment is to discourage mixing more than a novice can handle; you could stretch it to an hour but watch your mix because the rules say don't add any liquid to an old mixture because it will weaken it. Remixing just with an electric mixer should reactivate it, but this can only be done one, or maybe two times. You will be surprised how fast 2 hours can go by and 4 hours is much to long in my book. “TIRTGIM” Armen Tavy

There aren't any restrictions on larger tiles other than logic. Larger tiles are usually thicker and anything thicker takes longer to heat. As far as a heating systems location, the same logic applies. The further the distance and the more substrates that have to be heated determine the efficiency of any heating system. You also have to understand that the further the distance that heat has to travel also determines how long it will take to get there. Since tile heating systems rarely deliver heat that’s more than 85 degrees Fahrenheit, it will take even longer to warm the tiles enough so the warmth can be felt when walked on. Systems that are below the sub-flooring are not as efficient and have to “work harder” to reach their destination. They are better left on 24 hrs a day and that can be costly, or thermostats have to be set to go off at bedtime and turn on again several hours before wake up time, which means they would have to be on at least a minimum 19 hours a day, but if you get up in the middle of the night and have to walk on a cold floor, you may not be too happy. Do not plan to heat the entire room with a floor warming system because of the high heat loss factor. “TIRTGIM” Armen Tavy

Your best bet would be to picture frame the cubby holes with a narrow band of tiles.  You could even look for some complimentary Listel Deco Tiles to frame them. Look for Listelo Tiles that have a glaze on at least one side edge "TIRTGIM" Armen Tavy

If you don't want to damage the tiles, buy some heavy duty velcro tape and hang the picture that way or drill small holes thru the grout joint to insert picture hanger clips and hang the picture in the normal fashion. Remember a hanging picture leans slightly forward and one with velcro will stay flat and plumb with the wall of your backsplash. "TIRTGIM" Armen Tavy

You can actually soak the tiles in water for a short time and everything stuck to them should come off quite easily. Now the trick is to install them one by one instead of all at once on a sheet. The down side is that it will take you 36 times as long to install them but, that's not really that bad since you got a deal and you have the time. Well I assume you do. Remember to buy my appropriate size Tavy Tile Spacers to install the loose tiles. You also didn't say where these tiles are going. Are they going on a wall, floor or countertop? I'm certain they are porcelain Eric, so make sure you buy the best modified mortar to install them, however, because they are a small format, you can actually use a type 1 mastic to make your life a little easier, that is as long as the tiles won't be in a direct "wet area", which in time would eventual emulsify or soften the mastic, and that wouldn't be good........ Tell me what you decide and I will continue to help you.  "TIRTGIM" Armen Tavy

That's a large "cavity and that's what worried me and still worries me. I hope you tapered your walls wider at the top and narrower at the bottom so the side walls of the cavity could hold your new cement pour like "hands". You should have wet the area, used small to medium gravel tamped down and then packed coarse sand, tamped that down and then used a Concrete mix with Gravel. It's too late now and I don't have any suggestions at this point except for you to cross you fingers. As I said before, you just cant lay cement board like tiles. Your best bet, with no guaranty, is to lay galvanized "diamond" wire lath over the patch and let it overlap onto the old concrete by at least 12" in all directions and then pour a self leveler over the entire floor. The wire lath is only available in 28" widths and you will have to overlap any seams at least 4 inches. Tie wire lath sections together with twists of wire. You must use a primer for levelers as well.

Make sure you have help since this is not a one man job. Buckets of leveler have to me mixed as quickly as you can, back to back, so the seperate pours of cement can flow into each other. You also have to make a dam/s to contain the leveler and block any holes around the toilet flange, which obviously has to be "raised as well. Use a rake or squeege to move cement around as you pour. Your also going to have to figure out a way to keep the wire lath from "Curling up". You might think about buying several lengths of steel stock 1/8" thick and at least 1"-2" wide to lay on the wire to hold it down. Securing it with wire twists to the lath might be prudent. This combination will also strengthen and distribute the weight load on the patch as it bridges the "Cold Joints" you didn't coat with a bonding liquid. I'm crossing my fingers for you as well.

In the very near future, before spring hopefully, I'm intoducing a "Floating Tile Floor Underlayment System" that will "laugh at cracks" in concrete as long as the movement is "horizontal". Your entire installation would be like a magic carpet of tile and no one will be the wiser. No One! Watch for it. It's called, TAVY "008 Easy To Eliminate" You could even easily change your tile floors every few years, should you get "bored" with it.                 "TIRTGIM" Armen Tavy

Professionally formulated grout cleaners should be tried first. Ask for it at your local tile store. If this still doesn't work, you could use a specially formulated "Grout Paint" that's a breeze to use, comes in some colors too. The grout will look brand new and it will be protected the grout from future spills as long as you don't let them "linger to long". "TIRTGIM" Armen Tavy

I have to take a deep breath some times, or more truthfully a lot of times, when I read the many posts on this and another Tile Forum I moderate about jobs “Gone Bad” by so called professionals. I travel across the country two days, once a week, for 45 weeks out of the year and speak at tile training seminars about the “do’s and don’ts” in this trade. I don’t want to knock the many good professionals out there but it’s depressing to see many who are less than professional posing as professionals, and it’s not really there fault, it’s the system that allows the “have nots” to pick up a trowel and call themselves tile setters without consequences for their deception. As a professional with pride in this wonderful and artistic trade, I humbly extend my apologies to you and others that write to me, for the installers who pretend to be professionals, and leave customers brooding over installations that their hard earned money paid for.  I promise to do what I can, unfortunately from a distance, to help all those who write me. All I ask is that you all take a little extra time to give me as much detail as possible up front, so we don’t have to go back and forth many times to get to the “crust” of the problem/s. As far as duplicating or copying any tile installations you may view on the major bath and kitchen channels, think "THRICE" before you do.

 Forums like this are generally designed for simple answers for simple questions. I have a problem with that because there isn’t a simple yes or no to most questions when there are so many “Ifs” and “Maybes”. This forum has allowed me the privilege of giving longer dissertations to all that need help with their tiling problems. Although I don’t keep a time log, I’m sure I spend over a 100 hours a month answering questions and all I ask in return is a little feedback, so I know if I have helped.

The best advice I can give is, ask to see a contractor’s license, if your state requires one, and then ask for local job references, and then actually call two or three. Also check with your local Better Business Bureau for complaints that might be registered against your contractor or installer.

 Now, getting to your “simple” question. I can’t help anyone unless they give me all the information they possibly can. If you’re afraid or shy to call the person who did your sealing, don’t be, just pick up the phone, and in a calm voice, ask them to just give you the name of the sealer and the company that made it. Every sealer has a solvent that can remove it. Most sealers aren’t easy to remove and some are extremely difficult, as you have found. I will even call those manufacturers on your behalf, if you like, and post the answer I get on this forum. I’ve also never heard of a complaint like yours, and I’m very curious about what aerosol tile sealer could even cause what you have described. One thought just came to me, as I’m writing, and that is the possibility that the sealer may have been sprayed over grout haze that wasn’t polished off before spraying the sealer. “Grout Haze” that’s been on for 6 months and a sealer allowed to cure over it might explain the stains and the difficulty you’re  having removing it. “TIRTGIM” Armen Tavy

Please read post number 11785 to see if you're up to doing a ceiling and then tell me the size, shape and height of your existing shower and describe the tile as best you can. You can tile over tile with my TAVY "Thin-Skin" but, I have to know more, so I can give you the "Tips and Tricks" you need before you proceed. "TIRTGIM" Armen Tavy

I would go back to sleep and pray for a good dream. Sorry but, the "hypothetical" odds of your installation lasting are "0". You didn't "TIRTGIM" (Tile It Right To Give It Might) Armen Tavy