It’s up to the Kitchen Designer and contractor to put their heads together here. You’re basically building a table with posts and stretcher bars. It’s pretty darn simple to do it like your inspiration.

I agree this is like building a table the legs are the support at the one end and the cabinet at the other I would probably do the steel supports at the cabinet end just to be on the safe side . I don’t understand what you mean by a 12” overhang on the long side that is not part of the picture you posted.

Build it just like pic. Designer should be able to handle that.

I'd let a designer/contractor do the supports, but if I don't like it when I come to template, I'm leaving and not coming back until I do.

Contractor always constructs the supports. Designer typically engineers it. Fabricator should have proper surface prepared for installation. They should not have to alter anything.

Ok- thanks everyone for the feedback. I’m going to order the steel braces to support the 15” overhang. Does the 42” overhang need support other than the posts?drawing attached.

Island is 11 x 3 feet total with 12 inch overhang on long side.

I’m going to order the steel braces to support the 15” overhang.

Does the 42” overhang need support other than the posts?

What?? how many overhangs do you have?

An overhang is just that. a portion that 'hangs over' with no support from underneath it.

in the picture you posted, there is no overhang.

As for the diagram, no diagram posted.

In the pic w/the legs supporting the left side of the countertop, I would also have the fabricator insert steel braces into the plywood, just for extra support.

I'm surprised your GC isn't driving this issue. I talked to mine about a similar idea (but smaller in scope) and he mentioned 3-4 different ways they handled island extensions. I'm going to have an 8' long island, 6' of cabinet with a 2' extension cantilevered out. I thought I might need L-brackets to support it. Since I'll have 6' of stable counter top (thus a 3:1 ratio), he said they could route the plywood that the counter will sit on, and run steel braces the length of the countertop.

I think it's good to get ideas from people here but IMO it's up to the GC to own this issue, design it. and make sure it works. If you toss out an idea and there are problems, it seems like this GC is going to shrug and say he was just following your orders. Since you are working with a firm, I wonder if there is someone else in the company who can help with this. I can't imagine that no one in this firm has every done an island like this.

Ok, there is no overhang shown right?

You want to know how they will attach the table structure to the cabinets correct? Im over simplifying here but you have a table with only legs on one side and you will use the cabinet to support the other end vs having legs. Correct?

First off you are building a table and any basic carpenter should be able to do this. Actually you can buy the legs and even metal braces that take away any need for wood joinery. With some cross braces and a plywood top there will be NO weight issues.

As far as the cabinet I would double the plywood on the last cabinet. A simple piece of 1x screwed into the cabinet will support the other side of above described table.

Or to make it easier you could actually make legs n the other side and rip them in 1/2 so the would look like the styles of the last cabinets face frame.

Honestly this is fairly easy and if they are struggling say goodbye and find someone else. No fancy braces or metal anything needed here. Also dont forget to bolt or attach those outer legs to the subfloor or it and push on the bottom would act like a lever and can pull the leg right off.

Plywood is not nearly as good as a top support as is tube steel stock which is much more rigid. No steel on the flat please.

What is steel on the flat?

This.

Is that different than this- https://www.countertopbracket.com/product-p/iss.htm

Can u add a drawing of your island? if you are going to have an overhang as well as legs and apron, I’d be concerned about aesthetics as well as support. but Maybe I’m misunderstanding your design?

IMO that overhang makes no sense you usually use that for seating but in your inspo pic the seating is where the table type counter is this to me in your sketch is poor design

This is a better inspiration pic. This is the layout that works for us. Just need advice on the proper structural support. I agree this up to my GC but they have my money already and are being difficult. Just trying to educate myself before I accept what they are going to tell me.

Austin floor plan built in Wexford, PA · More Info

Joseph Colett,, do you have a picture of what you would recommend using? Thanks

If your KD can't figure that one out then you need a new designer. In principle it's just a table with cabinets underneath.

The drawing helps, just want to clarify that you are going to have apron/stretchers like in the inspiration pics (they are missing in the sketch). It is visually less pleasing and also less support structurally.

The island support also has to be integrated with the decorative elements. That can’t be an afterthought. In the island below, we used a flat steel plate with small welded flanges that aren’t visible. Flat steel is too flexible. The flanges add rigidity. Once the steel was designed, I then had to design how the steel would integrate into the wood.

The cabinet side was built thicker, to accept the weight of the bent tabs of the steel that had to be attached to it.

The blocking in the toe area is directly under the cabinet wall, providing support all the way to the floor.

The cabinet box was also routed out to accept those tabs, before it was finished, so there would be no exposed raw wood anywhere.

The steel tabs were bolted to the side, and countersunk, so that nothing protruded.

The decorative cabinet panel was routed to account for the steel support flanges, before being finished. Again, no raw wood anywhere.

The steel post accepts a steel locator pin that was location plotted, and drilled into the floor and subfloor. No kid will come sliding through and bang into it, knocking it askew.

The steel support was then finally installed to the cabinet side, and then the decorative panel was then applied over that.

That’s what went into that “simple” design. And seriously, it IS simple compared to some. But if your KD and GC isn’t able to do this? You have people on your team that ought to be back in the minor leagues sitting on the bench. This is is an ordinary day at the shop for any experienced Pro.

Island Style · More Info

Cooks, thanks for sharing all those details. That’s a beautiful kitchen. I love the stove plus built in over and warming drawer (it took me awhile to realize how much you fit in without the kitchen feeling cramped. Impressive). Do you remember the dimensions of the island, overall length x width and the amount allocated for the extension? I’ve heard that one key is the ratio of countertop that’s supported by the cabinet vs. the extension. (Want at least 2:1, right?) thanks

The island is 60”, and the overhang area is 36”. But it isn’t cantilevered. Cantilevered support is the 1/3-2/3 ratio for support without direct to the ground support below. This has the steel support post to the sub floor and the steel supports providing direct support. The difference is a bay window that protrudes from the face of a home, without a foundation underneath, vs a bay that has the foundation support directly underneath it.

This box bay is cantilevered, and has to have at least 2/3 of its support embedded into the house structure behind it, balancing its weight on the seesaw. This is like an island with invisible steel brackets, that need that 1/3-2/3 weight ratio to be stable.

This angled bay has a standard below the frost foundation underneath it to support it. It could be any size at all jutting out, because the foundation supports it. This is similar to a island table with support frame and legs.

Thanks so much, Cooks! BTW, do you remember the width of that island? Had you considered a narrower extension than 36”? I’m thinking of doing something similar with two barstools facing each other. I think I’ll have 33” inches, face-to-face, so people will have 16.5 inches for their knees. I’m thinking of allowing 24” for each place setting. I know that’s the minimum recommendation, and that 30” (or 36”!) would feel more spacious. My thought is that if people could sit slightly closer to the cabinet (vs. centered in the cantilevered spot), they could spread out onto the main countertop and it would feel more like a 30” space. (? the logic makes sense to me. Not sure if it’s actually sound logic, haha). Thanks!

If a KD can’t figure out that island support, your design is going to have much bigger problems. And I do mean BIG problems. You need to put several second sets of eyes onto that design to catch those problems. You likely need a different kitchen designer. One who isn’t there just to rubber stamp your cabinet sales sheet.