Whoever told you that you cannot install a floor warming system under tile over a plywood subfloor gave you incorrect information.

Your first issue is with the method of construction of your wood sub-floor under the proposed carpeting. Let us look at the possibilities. Plywood ideally should be installed over 2" x 4" pressure treated "sleepers" when adding carpeting on any below grade slab. The combination would ideally be a 2" x 4", a sheet of minimum 5/8”  exterior glue plywood, total height 2 1/8”. 

What you may have is the absolute minimum combination that I would consider sufficient under the carpeting, and that would be 3/4" pressure treated sleepers and a minimum layer of 1/2" exterior glue plywood with blocking under the seams. Total = 1 1/4". In any case, in order to tile the bathroom floor you would have to install 3/4" pressure treated "sleepers" and add one layer of 1/2" plywood with blocking, followed by a second minimum layer of 3/8"plywood or 1/4" cement backerboard, totaling 1 1/2' before the 1/4" for the heating matt, plus mortar, and tile. The addition of the heating matt or wires will add another minimum 1/4 inches plus 1/2" for the tiles you have selected. The finished floor in the bathroom would be higher than the carpeting at 2 3/4".

One option would be to install 3/4" pressure treated "sleepers", with blocking under the seams of 3/4" exterior glue plywood, plus allow 1/4" for heating matt or wires, followed by 1/2" for the tile plus mortar; total would still be over 1 5/8 inches. (You cannot substitute only 1/2" cement backerboards for the plywood, so forget that)

This only leaves you the only one thing that makes any sense. Raise the bathroom floor with 3/4 inches of self- leveling Portland cement, allow 1/4" for the heating matt or wires followed by 1/2" plus some mortar for the tile. New total height would be about 1 5/8" and that should be fairly level with the height of the finished carpet and pad.

Run some tests measurements and modify the leveling cement accordingly to suit your needs. I personally would add a marble threshold under the door to separate the tile and carpeting (to protect the carpeting from "wet" tile floors, either by accident, or when cleansing the tile with soap and water). I have given you all the possibilities, but this last option looks like the best to me. Armen Tavy

Although rounded corners in dry wall have a larger radius than 1/2". It will not be perfect arc, but you could use a tile "mud trim" called A-106 to make the turn. This tile can wrap around a corner that has a 1/2" radius perfectly or you could cut two pieces out of a field tile and cut in a 45 degree bevel on two tiles to make the turn; however, it would take a perfect hand to arrange and install the cut tiles perfectly plumb and in alignment with one another up a wall to any significant height, and more-so if the tiles were going all the way to the ceiling. You could use a Schluter trim to do this; however, it would take away from the "tile look".

Domestic A-106 trim pieces, aka "Bead Trim" (both are also referred to as one-quarter rounds) are still made by American Olean and Daltile in a large variety of colors, and one may match or compliment your tile color. Alternatively, the manufacturer of your tile may also make this trim piece. There are some tile suppliers that make larger format "bead" tile, so ask your tile supplier about its availability. Sticking to a pained surface in the "field" with tile mastic is possible; however, on a fragile wrap around corner the tiles may have a short lifetime. I wish you project was larger because my TAVY "Thin-Skin" would make a perfect surface to tile over on those corners. Of course it would be best to wrap the fabric at least 6" to 8" around the both sides of the out corners. If you chose to substitute my fabric for the sanding project, you could apply Thin-Skin" on all the painted surfaces and then tile with confidence. My system works with tile mortar or Type I mastics; however, acrylic or water base mastics are not recommended in the actual wet areas of a tile installation. You must use always use modified thin-set mortar in those areas. Armen Tavy

TAVY "Thin-Skin" to the rescue. As long as you do not disturb asbestos tiles there is no "danger' of asbestos migrating into your homes air. Although a single incident like removing asbestos tiles on a bathroom will not "kill you". However, EPA rules are rules, and no one is allowed to remove more than 25 sq ft of asbestos tiles without a” permit" and specialized uniformed help. Having said that, there is no harm in "encapsulating" the asbestos tiles with a product like mine as long as the tiles are secure and have s solid feel. Now there may be a likelihood that some of the tiles do not have the greatest bond after all these years but as long as they are not "floating around" a single monolithic membrane such as "Thin-Skin" can be installed directly over the asbestos tiles to create a substrate suitable to install another resilient floor covering. You could even install ceramic tile over the underlayment. Simple floor patching compounds can be used to fill any fractures and discolorations are never a problem with my membrane.

My underlayment, along with the multipurpose "007" Glue used to install it, is guaranteed to bond for at least 15 years and the only disclaimer is not tiling over wax residue, and if present, removing any is as easy as washing the floor. Purchase a liquid floor cleaner from your local grocery store that says it will also remove wax or wax buildup and be done with it. No removing, No scrapping of messy black adhesives, No sanding, just spread the "007" Glue over the clean tiles, imbed the Fabric into the glue while it is in its wet state, butt the seams together and stay off the fabric allowing it dry for at least 2 hours before walking on it or attempting to install a new resilient floor over it. The new floor covering installation could be delayed overnight or several days or more if you choose.

Any excess glue or glue that may ooze up between the seams onto the face of the fabric should be removed with a putty knife and the residue washed immediately with a wet rag. Again, avoid knee and foot traffic to prevent "dents" in the fabric by waiting the two hour drying time. Any accidental "dents" should be filled with a floor patch before tiling with any resilient covering. Combined cost for the 2-Part system ranges from a low of 55 cents to 80 cents per sq ft, depending on the retail source. One roll of fabric and one gallon of the glue will cover 100 sq ft of floor space as long as you are not wasteful while spreading the glue.

If your project is close to 100 sq ft, it would be prudent to buy an extra gallon of the "007" Glue. Left over glue can be used for a multitude of gluing projects around a home including the installation of your new resilient flooring. Only for other uses, would you let the glue go into a "tack state" before bonding two "porous" surfaces together. The glue is "light blue" in color while it is wet and turns to a "light green" hue when it is ready to bond to other objects. If your intent is to install new 12" vinyl floor tiles that are 1/16" or 1/8" thick, you would wait for the glue to reach its "tack state" before installing the new tiles in the traditional manner. If you are installing sheet “linoleum", you would install the linoleum while the glue was still in its "wet state". If you were careless in your clean up and you have areas where the floor is sticky from glue residue, sprinkle a little talcum powder over the sticky spot/s then sweep and vacuum the area.  Go to www.tavytools.com and click on distributors for sources. Armen Tavy

No official rules; however, butt joints are frowned upon. As tile sizes vary slightly or more, the larger the grout joint the easier it is to balance an otherwise awkward installation. I have proven in demonstrations that my TAVY "Tile Spacers" can actually do the balancing for the installer if the tiles vary no more than 1/16 inches, if all the tiles are "pack tight inwardly" against the spacers with pressure pplied towards the center of the installation. 

When counting sales of the different spacer sizes in my own line for the past 13 years, here is the order of sales with popularity nationwide: 1/4", 3/16" 1/8" 1/16" and 3/8" is last. There are other sizes but they fall into the less popular catagory for unknown reasons, and they are: 3/32" and my 1/32" which is the only Marble Spacer in the world designed especially for Marble and Granite Tiles, And the latter can probably be explained because many do not even know it exists. Armen Tavy

NOTE: 18" and 20" tiles look absolutely fabulous when they are installed with my 1/8" Tile Spacers.

I cannot help you other than let you ask your question here. Let us hope one of our regular visitors sees your request and gets back to us. Armen Tavy

Go to: www.granitecitytool.com and look for "Stone Tech" Heavy Duty exterior stone & Masonry Sealer. Armen Tavy

Believe me when I tell you Bill, that you pay for "Air" in the grout joiht when you purchase all ceramic tiles. The only products that are "nominal" as expected are marble and granite. You may have missed my tip on borrowing tiles from underneath a frig or stove. You have two tiles missing and they are side by side but you have not told me where they are on the floor in order for me to be more creative for you. The fact that two tiles broke side by side raise suspect that the entire installation may be faulty enough so the effort involved to relocate borrowed  tiles may not be as difficult as you may think.

Tell me more so that I can help, and before you do write back, borrow a golf ball from someone to test all the tiles on the floor. Gently bounce the ball from a standing position on every tile in at least five locations on each tile, the center and a couple of inches in from each of the four corners. If there are any hollow sounds, place a small piece of painter's tape on the tile/s on those locations. If all the five locations sound hollow place a much large piece of tape dead center to note those tiles specifically. Give me a "head count" when you are done. You may be surprised at the number of "hollow sounds" you find. Armen Tavy

Went to the link and was not able to open it with any success. As you mention, there are a variety of different drain systems and they can all work. Single pitch, to a "trench drain", or to an offset drain, with a more dramatic reverse pitch from the closest wall. Traditional shower pans have drains at or near center which also allows water to “soak” into/around a pan and weep out excess water through weep holes around the sub-drain assembly, and there are “positive” drains that work much like a fiberglass shower pan does. No weep holes to worry about, just a “positive drain” over a non-absorbent waterproof surface, such as the "Schluter Ditra" System.

Which are the best is best determined by their longevity without any problems, not including "plumbing leaks". Traditional "dry pack" shower pans were always considered the best, but they seem to have the most problems because there are many still who do not understand how to build them correctly. For a solution to this problem, others are using creativity to reduce "pan" failures by looking to other ways to drain shower water without the expensive side effects resulting from poor installation techniques. I find no fault with any system as long as it works, unfortunately it can take as long as ten years of multiple daily use to prove “theirs” is truly better over the other/s.

A traditional "dry pack" shower pan system with a waterproof liner, and there are several now, including pre-fabricated pans, is still the ultimate "work of art" a tradesman can be proud of, and it can last indefinitely if built correctly. However, even with the best construction, “Traditional” drain systems can harbor “bacteria”, festering mold growth more readily than “positive” drains. I have built single pitch (handicap) curb-less shower pans and they require precision planning; however, the 1/4" pitch per running foot of length must still be observed according to "code", and a 6 foot long shower must have a 1 1/2" drop from a level plain at the far end at a “trench drain” or at the center-point of a traditional drain in a 6 ft length at the far end in order to pass "inspection".

  note: "I hope this is not another test question from "PG")

If you look a my add in the right column of this forum, you will see TAVY "Thin-Skin" which I designed for installations that include your criteria. However, if your installation is going over a suspended wood floor, you would need to properly secure the wood flooring under the vinyl to satisfy the miinimum specifications as put forth by the tile industry. Wood under vinyl floors are never secured with enough fasteners for ceramic installations and whether you used my system or someone elses, you would need to apply fasteners every 8" in all directions in the "field", and every 6" along the perimeters of the room, as well as against any other solid objects.

The fasteners, alkali resistant screws 1 1/4" to 1 5/8" long or 1 1/2" galvanized roofing nails, are installed right thru the vinyl without a need for removal of same. My ceramic tile underlayment installation system is simple, and is similar to hanging wallpaper, the only difference being that the glue is applied to the floor instead of to the back of the paper, and you don't need a ladder. I am also always here for tips and tricks. Armen Tavy