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.

boone, I don't know if the same practices are used in SoCal as NorCal. I don't even know if the thickness of the plywood substrate is spelled out in some code. Does that 1/8" really make that much difference? Apparently my fabricator thought so. And my GC spelled out 5/8" specifically in our contract which was not otherwise rich in detail. Typical of him, I think he "forgot" and thought he could get away with reusing the old plywood from 1991. It does seem to be the norm in these parts (North Bay Area) to use 2 cm slabs on plywood substrate and a built-up edge. I only know and understand this after the fact. Please check with your folks down there, because I don't mean that my experience will be yours. It was a minor big deal for me, fabricators standing around fuming about the wrong thickness plywood, saying it would never do.

@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.

Real stone is overrated IMO. It has man-made processes applied to it to make it suitable for residential kitchens, as well as sealers, so being more ‘real’ is just marketing in my book, particularly for a surface you’re going to be cooking and eating off of. A sterile man-made product that is easy to clean makes more sense in a kitchen environment to me personally, which is why we chose white solid surface for our remodel. Our second choice was white quartz. It’s easy to tell if it’s clean and maintenance is a breeze. There are many many threads here on quartzite getting water ‘stains’ around the sink, seems, and stove, issues with sealing, issues with food stains and etching, poultices being applied, etc. The pale colors can be unforgiving. I personally think real stone is not a great choice for residential kitchen applications, at least not for working kitchens in the suburbs. In kitchens that see limited use where it’s all for show, or in old traditional working kitchens that utilize marble and embrace the patina, I can see the appeal more.