I have no idea why it's one way in some parts of the country and the other way elsewhere. I don't think it's an earthquake thing, Jakabedy. If it was, I think I'd have heard that while we were shopping around. I'm in the northern part of San Diego County. There are half a dozen granite yards within 5 miles of here and another half dozen or so about 30 min. down the freeway. Of all of those, with the exception of the place where we bought, the norm was 2 cm. And no, Lisa, these weren't cheap Chinese prefabs. There was a place we looked at that had prefabs and maybe they came from China, I don't know. One place was exclusively Brazilian, but most places had stone from India, Africa, South America, and probably some from China. Depends on the stone - some is even North American. I believe the yards carrying 2 cm had the occasional 3 cm slab, presumably because they wanted that variety and that's how it was available. The place we bought from carries only 3 cm because they prefer it. This place both sells and installs vs. handing over to fabricators. So we have 3 cm and we like it, but really, it's just a viable alternative, not a decision where there is a right and wrong. If Seattle has lots of 3 cm, how about British Columbia? Is there a preponderance of one or the other up there? We could actually map this out if people would say where they are and what they see in their area.

You can save some money by going with 2cm, but you they will have to "double up" the edge, so there will be a seam line where the two pieces join. How noticeable this seam line is depends on the quartz (and the quality of work too, I suppose)- the ones with larger pieces tend to show the line less. I've seen edge joints on counters where I noticed it immediately, and on others I could only see it if I got up close and looked for it.

@Alex P In theory, cabinets could be leveled to precisely the same height so that a countertop material would sit right down flat on top with no shimming. In reality, this almost never happens. Even with the very best technology in cabinetry leveling like using EZ-Level bracing which remains intact over time, you are still looking at having to shim a countertop of any type at least in a few places even in the best of circumstances. Regular cabinetry shims can shift over time depending on how they are applied, affecting your long-term stability prospects. For a countertop material that is already prone to cracking such as porcelain is, this becomes a great risk to try to shim that material with no underlayment for support, even at a 20 mm thickness. I would be more comfortable relying on the MSI guidelines for something like a small bathroom vanity countertop rather than a full kitchen where you will almost be guaranteed to need to shim the porcelain to bring it level across the largest run of your countertop area, thus leaving gaps between shims rather than the full support a subtop would provide. That is why you rarely see porcelain countertops without an underlayment unless it is for a small area like a bathroom. If you want the edge to be thin and polished without an underlayment, what this means is that you will need to specify your cabinetry to be constructed with full subtops and then somehow get them all perfectly level and ensure that there will be no shifting of the cabinetry or foundation in years to come, and then lay the porcelain down without shimming it if at all possible. Your idea of metal trim to cover an underlayment is creative, but remember that Schluter is designed to be anchored into grout, so you would need to be confident that you could secure it in an alternate manner before going that direction since you won't have any grout or tile adhesive in that area. I mentioned honed Absolute Black granite because it is much lighter than the polished type. Some varieties present in a gray color like concrete which is why your description reminded me of it. Soapstone also comes in a matte gray variety. I put soapstone in my own kitchen and love it, and it is considered to be a modern material for current kitchen design. Prepare for heartbreak if you do go with porcelain under any circumstances. Cracking and chipping with porcelain can happen, and it can happen to you, sometimes beyond any hope of warranty coverage. I liked the look of porcelain and its wear properties, but after much research including seeing cracks and chips in finished applications and talking to experienced fabricators, I decided to spare myself the risk. I have been thoroughly happy with the soapstone instead and recommend it if you cannot find anything else suitable. Even a honed marble like Danby would present fewer headaches for you than porcelain or concrete, I think.

Dishwasher is in and fine We have 2cm quartz now. The previous counters were 1.25” laminate. I assumed that a filler, leveller, or shim would have been added to account for the height difference as the quote indicated 1 1/4”. Removing the counters and cabinets sounds like a huge $ ordeal! I agree manufactures should provide some range to accommodate upgrades, however the provider of my counters should have identified there would be an issue.