Are you sure you're understanding him correctly? What is typical on the West Coast (where 2 cm stone is common), is to apply a piece to the FRONT edge of the counter that covers the edge of the counter and the edge of the substrate, thus turning a 2cm edge into a 3 (or more) cm edge. Very common. Best to ask for the edge to be mitered where the two pieces join - if they are, and it is done well, you won't even see it.

Here is the Midwest we use mostly 3 cm stone, but where 2 cm is used it must be supported with a plywood substrate. The proper treatment of the exposed plywood edge is just as sjhockeyfan325 described.

Hi, yes, I did understand him correctly. Because I was talking about not having visible substrate on the underside and preferring 3 cm as a more attractive option (for me). Of course, we didn't discuss whether there would be any extra cost for the application of the material to the underside. Ultimately, it will probably come down to the cost.

Thanks for your replies.

Unsupported 2cm is for vertical surfaces, for horizontal applications it needs to be thicker or supported or both. I am not sure of the visual that you are trying to accomplish, but if the unsupported area is too large and it came down on a person or pet you would never forgive yourself. You can always paint or otherwise cover the plywood backing. Unless you have sunk part of the room no one will ever see under the counter.

In rereading your post I'm not sure what lamination he is referring to. I would ask him what he is intending to use, as I would expect that he would use something like Formica which comes in a zillion colors and finishes.

When we were new to the world of 2cm vs 3cm countertops, this visual helped me understand (original post found here):

Regarding expense, we were informed by several sources that there isn't too much of a difference between 2 cm vs 3 cm. You'll pay less for the 2 cm material/slab, but more in labor (plywood substrate installation and additional 2 cm edge piece lamination). You'll pay more for the 3 cm slab, but won't incur the labor charges mentioned for 2 cm.

“Unsupported 2cm is for vertical surfaces,
for horizontal applications it needs to be thicker or supported or both.”

Not according to Page 3 of the MIA Residential Installation Manual:

“Generally, sound
varieties of granites and marbles can be used in thicknesses of 20 mm (3/4")
or greater without the use of a subtop.”

“In designs where the
countertop is cantilevered or overhanging the supports, the cantilever shall be
limited to 6" (150 mm) for 3/4" (20 mm) thick countertops”

"In designs where the
countertop is cantilevered or overhanging the supports, the cantilever shall be
limited to 6" (150 mm) for 3/4" (20 mm) thick countertops"

Hummm!

I don't think I'd trust that specification unless the material is amply supported. One good whack and that overhang would be gone and I'd get an irate telephone call.

Thanks for the replies. They're helping me rethink this. I suspect, as practigal suggests, that he means some other type of material. Otherwise, yes, the overhang would be overly heavy.

And thank you for the picture, javiwa. I didn't realize that the counter would extend out so far because of the application of the lamination. Not sure it appeals to me for our kitchen. In the baths, I will deal with it because I need 2 cm for the backsplashes.

A point regarding cost: we got bids from three different kitchen remodeling companies. With each, I discussed the cost of 3 cm vs. 2 cm plus the additional work effort for fabrication, suggesting a trade off. In each case, I was told that the fabrication costs are the same regardless of the thickness of the granite. Doesn't quite seem right but there was no flexibility in that area

Ultimately, the point might be moot depending on what is available in the granite that we choose.

Thank you all for your contributions to the discussion.