We had the bottom of our overhang routed out to fit steel supports which were imbedded into the soapstone. We provided the steel bars to our soapstone fabricator and they imbedded them.

YOu have several options. Not to have any support is not one of the options.

The pic of the embedded steel is one option. However, if the steel is not anchored to the cabinet it's little more than an expensive way to rod the stone (which is usually done with small diameter steel rod.)

For actual structural support you need corbels or steel that is securely anchored to the cabinetry. This is quite possible and the underside of the stone can be relieved (hollowed out) if you choose although the steel supports need only be 1/2 0r 3/8" thick so burying them in the stone actually makes for a weaker assembly.

the trick to low profile supports is getting a cabinet structure which will provide an adequate anchor points for the bolts holding the steel bars. This is usually not available without some additional structure built into the cabinets.

While it doesn't sound like a concern for your project it can also be important to have the cabinetry securely anchored. It's not uncommon for a raised bar to have only a half wall as the primary support structure and if you want to hang off a large overhang you need to make sure the stone doesn't want to tip the whole structure (cabinet plus stone) over. Seems like an obvious consideration to me but it's not for a lot of people.

We used the freedom bracket for our countertop support. I think we used 3 of them.

Here is a link that might be useful: Freedom Bracket

We will be anchoring the cabinets directly to the floor using 2x4s as a platform. malhgold did you install the freedom bracket yourself? how long was your overhang? weight/type of stone?
the carrier option also looks promising but no weight maxes on the website...

Here is a link that might be useful: Carrier

finally have a picture to attach that may be helpful. basically want to place a 70x66 slab on cabinet base that is 67x50. the 36" cabinet in the center rt side will be for a cooktop

You will have a very difficult time reaching the center of that island. I get why you'd like to do what you're describing but there are a lot better ways to go about getting seating that is more social. Your design is very awkward, difficult to execute, and expensive to create.

If you got that cooktop off the the island and put it against the wall where it's a lot easier and cheaper to ventilate, then you could so a much simpler and easier supported rectangular island with an L shaped seating arrangement around it. Then you'd be able to wipe the center clean without using a mop. And the overall functional flow of the space would be SO much better. It would be even better if you could manage a prep sink on the island.

We used a triangle of welded steel - angle iron for the "legs" and a rectangle of steel for the hypotenuse. This is then attached to both the cabinets and wall into studs. They just installed this today right prior to templating for the soapstone.

Billy,

I second what Hollysprings said. The support of the countertop is much less of an issue than the functional design of the kitchen. You should consider posting your kitchen layout for feedback from the experts here. Cleaning that island will likely need someone to climb on top of the island each time.

I routed a bunch of 3/8" x 2" stainless steel plates into the plywood subtop. I also have a couple post legs at the edges of the 20" overhang. The subtop is more rigid now, but I can still make a small deflection in the plywood if I put my weight on it. I don't know how much is enough, vs. overkill. I am trying to go without corbels, since the corbels aren't long enough anyway, most of them only go horizontal to about 7". After I took this picture I secured the metal bars with lots of epoxy.

This post was edited by scorpionleather on Tue, Oct 1, 13 at 3:40