FYI, I live in Erie, PA where we follow the 2003 International Plumbing Code, according to Erie's Uniform Construction Code. Here is a link that might be useful: City of Erie Uniform Construction Code

We were fortunate enough to have a basement kitchen that we could move into. Lucky for us, cuz we starting gutting kitchen in June, and granite didn't get put in till the end of November... one thing I learned, you don't really have a functional kitchen until you have a sink! Useful for us, little portable cart with coffee maker, and all coffee/tea supplies. We had tons of company that summer (of course! well-original completion date was supposed to be Aug 08! Ha!). DH and I preferred it downstairs, but our company wanted it upstairs (we had patio table set up in gutted DR)--honestly can't remember if we used hose or bathroom to fill coffee... Amazing how little space you actually do need, note my ~ 2ft of counter and most of the time it had a drying rack on it! We kind of enjoyed it...viewed it as 'camping with all the amenities"! Maybe part of it was the little table we had in basement was from our first apartment, so brought back pleasant memories! I had packed kitchen stuff in open boxes, so that it was reasonably easy to retrieve things. Seldom used items got packed away, and some never got unpacked...good time to get ruthless and declutter! This 'kitchen' was my craft room/plant starting room, so most of those cupboards and drawers were already filled with my supplies, I think I took over the large upper for plates and glasses, etc.

Do nothing...and install the LVP as-is. The terrazzo you have is a HIGH VALUE floor. I mean SUPER expensive to duplicate. I would 'give up' on the warranty of an LVP floor and just toss it in. To do anything to this floor will ruin it for future generations. To level it you would have to grind, grind, grind, grind to get SLC to grab. Once you do that, you have lost the value of the item. At that point, you might as well spend the $3/sf to jack this out. It will be worthless. The TILE is see in the background can be left in place, you can do a bit of grinding and then fill the grout lines with SLC. You need to do some scarification of the tile to get the SLC to GRAB the tile. So long as it grabs you can fill the grout lines and flatten it to the best of your ability. I would EXPECT to use T-moldings where the two floors meet. The only way to avoid this would be to remove it all. In essence you are covering the HIGH VALUE products with a lower-value product. I get it. The current floors are not very attractive (compared to today's trends). But realize the value of the terrazzo. If you were to replicate the floor today (with modernized product) you would be looking at $25-$30/sf. Compare that to the $4/sf product you are going to cover it with. Right. LVP is a downgrade compared to terrazzo. No way around it. I would leave the terrazzo in tact and untouched. I would give up on any warranty and install the LVP over top. The tile can be dealt with as you wish. But remember to put in t-moldings between the LVP sitting over the terrazzo and the LVP sitting over the tile. NO underlayment. Most LVP's do NOT allow underlayment. Especially if they have attached underpad. This is LVP not laminate. If you want to get a cork underlay on these floors to help even out the surface then work with $4/sf laminate. That will buy you a TOP OF THE LINE European laminate. You can then use 6mm cork to correct some of the unevenness. But LVP will not allow that type of underpad.

OK...Contractors are NOT tile setters. Let's get that out of the way right now. Tile setters are EXPENSIVE...so General Contractors (GCs) do NOT like to use them...they loose too much money to all that professionalism and knowledge and correct way of doing things...and all that junk! So...to be clear, you need a TILE SETTER! Not a GC to lay tile. We've seen THOUSANDS of RUINED of tile installs laid by GCs themselves (they REALLY try hard to save money by doing it themselves....they only pay-out to Electricians and Plumbers...everything else they DIThemselves). So...onto your situation. You have a SLATTED subfloor. That's big, bad news for tile. That's expensive for a proper install. This CAN BE DONE...but it ain't cheap. You need smooth and flat. You also need to know your deflection rating. And you will need a decoupling membrane. What it sits on will be determined by the TILING PRO you will make your GC hire. Oh...that part requires a new negotiation for an increase in costs....which you will pay....but that's a different thread. Some will use backer board (if the deflection rating is CORRECT). Some will use plywood (if the deflection rating is NOT correct). The screws (galvanized please) will then be patched to create the smooth. And the decoupling membrane will go down and THEN you start the tiling bit. Floor Tiling Over Timber Like a Pro - Bing video Notice this guy is British...and has a 3 month waiting list....? Here's how you start in N. America: National Tile Contractors Association (tile-assn.com)