I use A LIPPAGE system on most tile larger than 12x12. I think you are confusing it with the term Leveling. Leveling the floor will happen prior to tile setting to get it in spec for the large format tile. then a Lippage tuning system will help with the install and settling of tile as the mortar pulls. You can in many cases end up with a Lippage free floor that is IN plane and flat but not LEVEL. sometimes this can be corrected with floating as one sets. You will find Lippage systems are used on 3'x8' slab porcelain tiles all the time. This small floor was 5/8" out of level from left to right. Staying withing the limits of medium bed thinset mortar I was able to float these larger tiles LEVEL and use a Lippage system to assist me keeping it flat and lippage free. As well You may be dealing with an old pro that wet sets there tile and floats with a level as they go, they may not need nor care for lippage tuning so youre question is very hard to answer as to whos right...

Yikes.... I wouldnt waste your time taping off grout joints. The glazed wall tile (in your original pic will clean up nicely. The floor Tile should be pretty easy to clean as well unless it has a texture or grooves in it. You can grout the faces of a sample tile to see how easy it is to clean. If in doubt you could Pre-seal the tile before you grout. Dont use additives much so can’t give you feedback on that. The laticrete product mentioned I have used before and works well. but mostly my suppliers carry Mapei and Custom brands of grout. For cement based grout I like Custom Prism or Mapei Ultracolor. Both are color consistent and fast setting. Both work well if installed following manufacturers instructions.

My first question is: Is this a tiling PROFESSIONAL? As in, ONLY does tile for 30 years? Tile setters rarely have more than 20-25 years of work in their 'knees'. At that point, around about 55, they start having to have surgery to correct the damage their trade has done to them. A General Contractor who does everything, will often have 30+ years in the business because they do not do ALL the work. They do some, but often they will put themselves on the side lines and manage the jobs. They are 100% RESPONSIBLE for ANY WORK produced by their subcontractors/employees. If the installation is wrong (goes against any/all installation requirements) you have every right to require a redo. Every right. Tile setters are NOTORIOUSLY expensive to hire for these GC firms. For that reason, many GCs prefer to do the tile work themselves. It saves them HUGE amounts of money. As in the ENTIRE mark-up for the job. In my neck of the woods, a large format tile (which you have) has an labour cost of $12 - $15 per square foot. Materials are extra. In my area, your 600sf would be $7,200-$9,000 just for the labour. Feel free to check that against your contract. Do you have photos? Some of the old world guys will still float their surfaces before installing tiles. The rest do Self Leveling Concrete (SLC). To do that, you need to rough up the concrete a snick and then clean it (really well) and then you can add the SLC. That takes time = $$ and that takes effort = $$ and it takes materials = $. I've seen concrete slabs require $5/sf of preparation. That is worse case scenario...but still. I always tell my clients to budget $2-$5/sf for concrete slab. For 600sf I would have told you to sock away $3,000 JUST for the slab prep. If you use it, fine. If you do NOT use all $3,000 then you are in LUCK! Long and short of it, The 50% off-set is wrong (unless the tile specifically states it is allowed). You were correct with the 30% stagger/offset. You were correct with the leveling system/spacers. The place to find your smoking gun: The INSTALLATION instructions for your tile. That will have them 'dead to rights'. A full redo can be negotiated...or a BIG chunk of money given back and the two of you part ways. I'm a realist and I'm practical and I'm very motivated by budget. If I have an OK tile install AND I have $$$ money in the bank because I've gotten a decent refund (like all the cost of labour returned to me), then I'm grabbing the cash and making a dash for the bank! But that's just me. Try to load some photos. While you wait for 5 minutes for the photos to load (need them in jpg) you can search the internet for your tile install instructions. If you can't find them, give us the name of the materials you used. We'll dig them out. Flooring pros know where the manufacturers hide them (sometimes it takes 12 different links to get to ONE set of instructions...they do this on purpose). I'm sorry this is happening. I hope you can negotiate a BIG fat refund. If this is a GC, it will teach him to bite the bullet and hire a tiling pro for jobs like this one. Sigh.

poor layout. those sliver cuts against the wall should never be there.(you adjust your layout so you do not end up w/those against the wall. he's lazy) I'm guessing you had a poor quality, or cheap tile installer. 1. the floor wasn't leveled. 2. He doesn't understanding that large tile like that can only be offset by a max of 33%. (you have 50%) All you have to do is look at the spec/install recommendations for that tile manufacturer and they will tell you. (sometimes it's on the box). Did he use any of these leveling spacers? (i'm guessing no) How much mortar was used on the backs of those tile? he should have 100% coverage on them. (not blobs placed here and there) Rap on the tiles. hear any hollow sounds? So, to answer you question, it was a poor quality layout because of the lippage, the sliver cuts in the back, and the 50/50 layout (and prob no full coverage on the backs of the tiles) Personally I hate the quarter round molding next to the baseboard. He couldn't have slipped those underneath? Or he couldn't have cut them perfectly flush w/the baseboard? Or, how about just replaced the baseboard or removed it? The white shoe molding next to the beige baseboard molding looks cheap. Is it livable? yes. up to you what you want to accept based on the price you paid.