A real tru tile setter can float there tile FLAT. We used to do this with wet setting on bigger tiles, Now we have medium bed thinset mortars that can be used up to 3/4" of depth under the tile so we can float to some extent with that.

Floors are not always level and thats OK we are more looking for FLAT and in plane. If you start with a FLAT substrate that meets tolerances for TCNA/ANSI I dont always use lippage tuning. It comes down to a job by job basis, The quality of the tile, and many times the material budget.

The one and only excuse for lippage is the tile material itself. If its warped / bowed etc. If the substrate is not in tolerance before I tile I know I have to float. If im floating I make sure its within 3/4" depth for my thinsets or I will sometimes wet set in which case I will level as I go.. Usually I fix the substrate first or skip on the job if they dont want to do that $$. But you dont get a floor with a bunch of lippage and I dont get a bad rep.

Actual well installed marble floors can be polished and some lippage can be mandated. Its not cheap. We had a recent post here by one of our skilled veterans in it he speaks to bending tile with lippage tuning to force stagger patterns..... I have on occasion taken jobs with bowed tile and forced them somewhat into submission with Lippage tuning like that and it can really help (but thats not a spec and adviseable to try for many)

lippage tuning doesnt LEVEL a floor it helps keep the tile flat and in plane. Leveling happens underneath and before tiling or via wet setting/floating. I have set 24x24 tiles with no tuning system just fine so you dont neccesarily NEED it always.

Off topic:

Its a great post you have here, we are in a market these days that tells people do it yourself, watch youtube and HGTV ....... as such weve got a bunch of novice diy tilers turned craigslist PRO that cant get the job done right. Usually half the price of A pros price and Homeonwers are getting the brunt of it while the entire tile industry remains largely unregulated on local levels and gets a bad rap daily here on Houzz...

"Help Total tile debacle" " Why does my shower floor look wet " etc etc. But we dont get the full story, People claim to hire tile pros when in fact they show us no proof or paperwork, no company names, where they sourced the install etc. and I think a lot of what we see here on Houzz is folks hiring cheap labor off craigslist and trying to manage their own renos' getting in way past their depth and then coming on houzz complaining and not sharing all the facts thus making the entire PROFESSIONAL tile industry seem shady.. Not all of em but im sure its a serious number and I see it here in my own backyard all the time. Is that how you ended up here asking this :):)???

Thank you for your thoughtful response.

I think that skilled trades people and athletes share a lot in common. Michael Jordan could dunk a basketball from the free throw line and he made it look easy. When I go into my backyard and brick a layup off the rim then think back to some of the feats of skill and raw physical ability that almost all professional athletes are able to achieve, I have a greater appreciation for what they do.

I'm at a point right now where I want to learn. The first step is always developing the vocabulary. Any activity worth doing has it's own specialized vocabulary that goes with it. Doctors, lawyers, trades people, and athletes all have specialized vocabularies that are tied to their areas of expertise.

You learn the vocabulary and then use it to gain knowledge within that domain which shapes both what you see but also how you see it.

With laying tile or almost any activity that requires both specialized knowledge and fine motor skills, it's hard to appreciate greatness unless you have stepped onto the court yourself.

I laid a small amount of tile. I'm not 100% happy with the results, but I did it to gain a deeper understanding of the whole process. I may find that in a year, I'll rip it out and redo it with the knowledge I gain in the intervening months.

I could also see myself hiring a professional, using what I learned to make a better decision about which person to hire and what fits within the bounds of professionalism for his field of expertise.

For me, it's not about the cost of doing a project or about how to do a project to save money. It's about learning and about developing an eye capable of appreciating those things that are remarkable but will go underappreciated if you haven't invested the time and energy necessary to see them for what they are.

I work in a large city and am surrounded by buildings filled with some amazing tile and stonework. I don't think I would have as deep an appreciation for the quality of the craftsmanship if I didn't install this small amount of tile, notice that I produced some lippage and think "I'm not satisfied given what I see can be achieved."

thoughtful response or a Rant? !

I started my working years at 15 @ dairy queen. Man my boss could fill up a perfect cone and dip it upside down in the hot chocolate and BAM perfect. Time honed skill. I lost a lot of ice cream in the chocolate those first few months. :)

I'm not a 'go over' fan. If you don't like the tile, demo it. I had several big tile projects in my home, and I bought a quality MK tile saw and a Hilti demolition hammer. These paid for themselves.

The main issue is subfloor preparation, and the floor deflection. The amount of deflection is determined by the size of joist (like 2x10 or 2x12), the spacing between the joists, and the length of the span. John Bridge forum has a defection calculator.

There is a minimum deflection of 1/360 for tile, 1/720 for stone. You can 'beef up' the subfloor with 3/4" exterior plywood, screwed every 6-8", with staggered seams, perpendicular to the floor joists. Next you spread thinset and screw down 1/4" cement board. The thin set is important - it fills the voids between the plywood and the cement board.

If you floor is flat (doesn't have to be level) you are ready to tile. If not, you will have to use SLC (self leveling cement). Once you have a flat floor there is no reason to use a tile leveling system.

You spoke about tiles being 1/2" or more in thickness - there is thinset made for heavy tiles - so the tile doesn't 'sink' into the thinset.

Remove some tiles from the box, and put them back to back. If there is a gap in the middle, or at the end - this shows you how much the tile is warped. Larger, longer tiles have a tendency to warp when fired. So the manufacturers suggest that you lay the tile with about a 1/3 overlap - this minimizes the lippage.

I back butter all my tiles (cover the back of the tile with thinset, then scrape it off with the back of the trowel.) Apply the thinset to the floor in a horizontal manner (not swirls). Lay the back buttered tile in place - tight to the one before it. Then give a little push away - that will provide good contact.

I'm not a pro (I'm an Engineer), just a guy who is good with his hands.

Thanks guys. I feel that I dropped my first ice cream in the chocolate recently. You both have been very helpful.

I am an engineer too and I did work for four years as a carpenter when I was much, much younger. I am very familiar with wood and construction in general, but I've never worked with stone and tile. It's a slightly different animal.

Some of the posts regarding waterproofing showers, tile selection for recessed soap trays, and various other discussions regarding both materials and techniques have been invaluable.

When I was working as a carpenter I'd frequently hear one person say to another "you have to be smarter than the board you are working with" and with tile I think it's important to know enough so that you make choices that don't require you to fight against the materials you are using.

I learned a lot. This has been great. Thanks.

I bought his book. Reading it now. Thanks

OK--you are talking floor--horizontal surface-and problems w/lippage where surface is not completely level...

I was going to mention how light from above can cause lippage on vertical surfaces (like shower wall) to be seen more readily than w/o the light source... And how light sources should be taken into account when using tile on vertical surfaces...