What thickness and type of granite?

I'm not sure about the "engineering" aspect of what you are describing but our 11 foot island had to have a support built in. I can't remember the terminology but maybe one of the builders on here can. A tension box maybe? We did the corbels for decoration only they are not supporting much.

We got ours from Enkeboll

Man, my house is dusty. About an inch thick in this photo.

Our bar tops are 16 inches wide with 3cm granite. The step up wall for the bar is 3 1/2 inches wide and the corbels are about 6 inches deep set at about every 5 feet (leaving an overhang on the cabinet side of 1 inch and on the bar stool side of about 5 1/2 inches beyond the corbels). The whole set up is VERY solid. I have no concerns.

I have the flush mount version of Rakks. Overhang is somewhere in the 14" + range. They work great for us as corbels didn't fit in with our motif.

Here is a link that might be useful: Rakks

I just installed several pieces of 1X10 (+/-) flat metal plates purchased from Lowes (or HD).
You do have to notch out the the depth (about 1/16")of the plate onto the framing wall for a flush installation with your countertop. These plates do come w/ predrilled holes and I fastened them to the frame at 2 locations per plate.

Flat metal provides very little additional strength in this application until it gets pretty thick (like 1/4 inch).

The granite guy I use grooves the bottom of the granite and beds angle iron (1/2 inch x 1/2 inch 3/32 thick) into the underside of the overhang if it needs additional support.

It depends on what type of granite and the amount of overhang.
Someone IS going to sit on the overhang at some point.

We have metal bars fabricated that were installed under teh granite--they were attached to the front of the cabinet (side without the overhang) and then extended across the top of the cabinet under the granite to the edge of the granite overhang (a groove was cut into the back side of the cabinet (the side with the overhang) for the bar). I don't remember how thick the steel was, but the bars were very heavy. The bars were attached to the front of the cabinet so that when you leaned on the overhang it wouldn't tilt up and slide off.

Hi,

I had this same dilemma when I installed my breakfast bar with a granite countertop. I didn't want to use corbels or other supports because I didn't want folks banging their knees and I don't like the look. I like that 'free float' look also. So, I actually purchase a custom cut metal plate, screwed it to top of the breakfast bar supporting wall, and then just layed the granite right on top. Make sure that your wall I had to go to a specialty machinist shop to get the metal plate (roughly 10 gauge), and they laser drilled holes and countersunk the holes so that I could screw flush into the metal. This is not sheet metal. It's a very thick, very heavy metal plate. I had screw holes countersunk and offset every 8 inches along the sheet metal. Also make sure that your top 2x4 is securely mounted. If you can add a 2x4 between each stud (directly under the top board, side nailed into the studs). Then, you can screw through the metal sheet securely onto not just the top 2x4, but also the 2x4 directly underneath it, giving you a very sturdy base to lay the granite on. You don't want the weight of the granite to rip the top 2x4 off.

You can see the whole project at http://www.thegoodrumfamily.com/ayrlee.kitchen if you look at the pictures under the Saturday section and you can see the metal sheet, and see a small section how the top 2x4 is reenforced with another 2x4 underneath.

Here is a link that might be useful: Ayrlee Kitchen Project