Our research showed the lower cost of 2 cm is offset by higher fabrication/install costs (no laminated edges/hiding the plywood). Also, you can look at it the other way: the higher cost of 3 cm is offset by lower fabrication costs.

On the 2 cm, the undermount sink will simply sit on top of a simple hole cut into the plywood. On 3cm, you may have to anchor it into the 3 cm stone from below and is a bit more work IMO.

The are pros and cons to each 2cm vs 3 cm. Three things I can think of that can affect selection:

1) Edge preferences and granite pattern - if you want a thicker edge, then 3 cm offers the ability to go with a 3 cm edge without any lamination. This might be important if the selected granite has prominent swirls or veins that would look broken up on smaller laminated edge piece. However, if the granite/stone is more uniform, the lamination seem can be hidden well or simply won't be distracting.

2) Overhangs - the 3 cm can overhang much farther than a 2 cm/plywood without corbels (supports). Search the forum or check with fabricator for overhang recommendation. If you don't have an overhang, or plan to use corbels, then there is no difference 2 cm vs 3 cm here. If a large overhang is really important and you don't want corbels, keep in mind engineered stone overhangs farther without supports than natural stone - something I ran across in our own research. They also make some nifty steel beams (forget the trade name) that can help support overhangs without sticking down much, but that adds to costs.

3) Availability. Might be harder to find 3 cm on West Coast, and 2 cm slabs on East coast of what material you prefer.

-DH of gsc

Thanks for the info, Grace's DH! I'm in TX and apparently both 2 and 3 CM are plentiful. There's a lot more to this granite selection than simply color, lol.

We recently installed 2CM prefab granite in a second home in Texas and it turned out great. In prefab granite, the edges are already laminated and finished and they cut to fit the length you need. I did have to take a marker pen and darken up the edges of the plywood in a few places so it wouldn't show. We found prefab 2CM to be quite a bit cheaper than the 3CM in Houston. Prefab has fewer color choices.

If your fabricator charges by the installed square footage, he will likely charge you for more area with the 2CM because of the laminated edges.

Every guy has his own method of arriving at his final cost to you as his customer.

Personally, I don't care any more - because I am Not usually the guy that's actually
lifting the stone (when it's 3CM).... HA!

Some guys prefer 2CM because it's lighter in weight 15 lbs per sq ft
versus 22 lbs per sq ft for 3CM. Believe me, when you've been lifting 2CM
forever - 3CM stretches your arms out!!! (or at least it seams like it at
7 lbs per sq ft more in every lift you make)

As far as a consumer goes - either will work fine if Fabricated properly.

It's totally up to you - so trust your heart and go for what YOU want in YOUR home!

hth

kevin

Thanks, everyone. I appreciate the responses. Can anyone comment on how the undermount sink and dishwasher will be secured under the 3 CM? I've heard the term "sink cradle" but I have no idea what that means. The fabricator will be here tomorrow to measure, so I'm going to bombard him with questions.

Don't want to steal the topic, but my fabricator says he wouldn't be using any plywood backer for 2cm! Should I be concerned?

southernstitcher--as you see I am far from the expert, but it is my understanding that the plywood is to bring the 2 CM to standard counter height when installed. (Of course, I have no idea what I'm talking about, haha.)

Hmmm, so 3 CM is 7 lb/sq ft heavier than 2 CM? Wow. That's a lot of weight.

Steff1--I'm not familiar with prefab granite. Was your project DIY? (I'm in the Houston area, too.)

Yes, I would be worried. I think you need the plywood for strength as well as for the height.

Southernstitcher-

The guy who is saying he's not going to use a subtop on your 2CM stone
obviously has not got a lot of experience behind him. ALL 2CM tops
should be installed over a 5/8 inch thick plywood subtop - ACX grade
or better (ACX means that one side is sanded very smooth).

DO NOT use anything other than plywood for the subtop when installing 2CM
thick tops. 3CM does not need a subtop - in all fairness to the situation,
maybe your guy meant 3CM.....

I have been doing this gig since 1985, and I see failures all the time, where the
installers either omitted the subtop on 2CM, or used something like flake
board, melmine or OXB, and when that stuff gets wet - it expands. The stone
then fractures, and then I get a call to come and look at the nightmare, and
offfer my expert forensic opinion on what caused the fracture..... If more
guys would do things right, I would not have to inspect as many failures, and
hence, be lighter in the bank account..... oh well - you can lead a horse to water......

hth

kevin