Overhanging Granite Countertop

You should consult the granite supplier, but here are some support methods that have worked in the past. July 29, 2012

Should a 12" overhang for an eating area of an island have corbels for support? If not, what is the max unsupported overhang you would be comfortable with? I always use some type of corbel, for both decorative and support purposes. I have a designer on the current project saying that a support will not look right with the style of the kitchen.

Forum Responses
(Cabinetmaking Forum)
From contributor F:
When these questions come up I always go with the advice of the person who has the most experience and more importantly responsibility for the end result. I'd call your granite supplier and ask them if it will fly ahead of time.

From contributor M:
I always add a bracket or corbel at 8". My granite guy says 8-9" max free overhang. I would definitely check with the granite supplier you will be using.

From the original questioner:
I do plan on checking with my granite guy, just wanted to see what others do as well. My gut says 6-8" max. People always lean on the counter when they are eating or just sitting. All it takes is a weak vein in the granite, and you have some broken toes or worse.

From contributor D:
There are ways of supporting your countertop without corbels. Pass along the expense of a metal subtop hidden by a wood apron.

From contributor E:
It depends on the thickness of counter. 2cm 6", 3cm 10", 4cm 12", and so on. It also depends on the granite as some granites are not true granites and are softer.

From contributor E:
I always defer to the granite shop for overhang supports. What we have done is liquid nail and screw 1" ply to the top of the wall. Then put trim around the ply to match the cabinets.

From contributor W:
There are some rules on this, over eight inches add support.

From contributor M:
Outwater has some metal bars that get screwed to the top of the cabinets. Canít see them unless you are lying on the floor. As others have said, talk to the granite people as they will ultimately be responsible.

From contributor Y:
If you want to get away from corbels and brackets you can get 1/2" X 1 1/2 solid steel bars and either lay them on top of the cabs if the top is 3/4 or else glue them to the top and notch them into the frame. It acts like a stiff back and works really good. Also, you can use 1/2 angle iron rabbited into plywood and install per above. This works really well - I space them every 2'. I used these for a 16" overhang.

From contributor J:
I did my own bar with 12" granite a few years ago. I donít like brackets, so after researching I went to a 3/16" steel plate mortised into the cabinet tops 6" back from the edge. The steel shadows the granite overhang an inch back from the edge. I wanted the steel to fight the load so the mortises were deeper away from the edge, kicking the steel slightly higher than level out at the edge. It was a WAG on the pitch, maybe 1/8". I went around the transition edge with construction adhesive like caulk. I covered the whole underside with polyurethane, and happy ever after.

The steel was screwed down into the mortised cabinet partitions and ends along the inner edge. Check if your cabinet verticals have enough thickness to hold a screw before trying this stunt. The granite guys had never seen this before, but thought it was viable, and set the tops without problem.