If the fabricator says it needs reinforcement then it does.

Change your move date if you need certificate of occupancy, otherwise you're moving into an unfinished home.

The stone fabricator likely will not engage unless their request is handled as the risk is not worth the job as is.

Our cabinet builder supplies plywood decking with all orders. The island has steel inlaid extends across the cabinets & out into the cantilever. Its rabbited into the top of the plywood and concealed underneath. The ply is 11/16". The doors are also set 1/4" below the top of cabinet. This allows for 2cm slabs with a 4cm edge. If you're using 3cm material the spec is different.

If you don't have this space it needs to be created.

Alternate newer product available at Dal Tile are honeycomb structural aluminum sheets.

Show a photo of existing.

You had a poor kitchen designer to not design this with the correct support from the beginning. Did they not factor in electric outlets either? Give up the unsuitable, overdone, and cliched waterfall, and move forward.

"has a small 3 in wide ledge on top to hold the wire and lighting strip to illuminate the panel... we can't notch the cabinets to install the brackets because of the light strip- not enough room"

This disco lighting counter/panel look is early 2000s. I would not do it, and certainly not do it given the difficulties you are having. Honestly, I'd ditch the waterfall - there are so many posts on here about all its problems, and limitations of the counter, and the issues with electrical, and scribing the waterfall properly to the floor, and having the veins flow in a pattern, trying not to have a gap between the waterfall panel and the island cabinets, and chipping the edges, and, and, and.

The look now is an extra thick counter, no waterfall, and the stone has a mitered built-up edge to achieve that look. Probably too late for you, but I'd ask the fabricator to stop the waterfall, and get on with your kitchen and your life.

"The other side is a wood veneer design panel which is 3/4in thick but has a small 3 in wide ledge on top to hold the wire and lighting strip to illuminate the panel."

" Problem is we can't notch the cabinets to install the brackets because of the light strip..."

I don't understand the bolded text but could you either (a) cut a shallow groove into the underside of the slab for a recessed channel and LED tape light or (b) attach a surface-mount channel and LED tape light to the underside of the slab?

The stone would always have needed support, so do not blame the holdup on the responsible fabricator. It is your clueless kitchen designer who has created this situation. The island has to be redesigned. Throw it in the lap of the design shop owner to solve, since their employee messed it up. But the design brief given the designer by you was defective as well. They should have talked you out of a lot of that. Most of that. Or just said no. The lighting is especially cheesy. Get rid of it, and part of the issue goes away.

I am not generally a fan of the overused waterfall design, but I think this is a proper use of it. It is a nice design. (I'm not sure your drawing shows 2cm but that doesn't matter.)

I would omit the light strip (that will always be cheesy and has always been) and support the countertop as the fabricator deems suitable. You're putting stools in front of the panel--no need to light that up. If you really feel the need for a light strip, get a different type.

Thanks for everyone's input.

The cabinets are installed and at this point I can't really change the design from waterfall. they came from Poland and the sides are not finished to be exposed.

I agree that this was a miss in the design process for sure. The islands are also bigger than expected by about 6 inches was caused another nightmare in trying to find slabs that we big enough. Anyway, i just have to deal with what i have at this point.

the light strip on the wood panel makes sense because this same design panel is in the backing of some glass cabinets on the wall which will be illuminated as well. It will tie it all together, hopefully lessening what some of you find to be cheesy :-)

I will post some photo of actual install tomorrow for anyone interested.

So does anyone here thing the mesh and epoxy alone is good enough? GC says since the unsupported overhang is about 11 inches and the total width is 38 in it should be ok.

If the stone fabricator says you need the support, you probably do. This isn't the sturdiest stone so it might need a little more than your GC realizes if he's used to granite or manmade quartzes.

Your GC is NOT correct, and just wants to finish the project and collect a check. You are going to have to redesign the island.

The original design is not compatible with all of the design requirements. Either the lighting has to go, or the overhang has to go. That is the only way to fix this in a relatively short time frame.

Or, redesign the entire thing with a taller counter, and wait months for more parts to fix it. You can move in with a temporary plywood counter. Many people have done that.

Deal with the supports and just move the light strip down a little lower - it should still be fine because of the angle you are viewing the island.

Plywood countertop will do the trick until you can work it out. It won't be the first time.

With any reinforcing rod solution, your fabricator had better bed the rods with the good expensive stuff,Integra Surface Bonder Ultra which doesn't bleed, exposing the rods.

The support should have been decided at the beginning of the project and what possible use is a 9" overhang . Waterfall islands are best in very contemporary kitchens and t\lighting it is so passe I can't get my head there . The steel rod frame should have been part of this construction from the beginning and IMO ther eis no way you are moving in with this finished in 2 weeks. Where the heck is you kitchen designer that is who should be dealing with this not a bunch of us who have no clue waht else has been screwed up.

Put down some plywood, and put a bunch of money in escrow rather than paying the final payment to the whomever got paid to make this work. Figure out the compromise that you are willing to accept if you want this done before closing. Be prepared to wait 6-9 months for the full redo that this requires if you are not willing to compromise. This is where having a kitchen designer who is fully experienced with high end frameless cabinetry is vital. It's also vital for a project with a deadline to have sources much closer to home, with a shorter time frame for expedited redos.

Trust your fabricator.  You do need some steel supports. You have a 14" overhang spanning a width of 120".  If you really want the lights,  I would remove them,  install steel supports, then find a way to add some lights in between the supports.