Granite Overhang Limit

Granite Overhang

Granite Bar Top with Overhang

We are installing a granite bar top in our new kitchen remodel and the question came up…how far can the granite overhang before it needs support?  We have a 2×6 wall below the bar top.  The bar top is 18″ wide and we plan on having a 1.5″ overhang on the short side.  Attention all math whizzes, what does that leave us for an overhang dimension?  You are correct if you answered 10″.  So, the question is, do we need any supports or corbels to support the granite overhang?  There seems to be a great deal of uncertainty on this subject.

Granite Overhang Limits Per Experts

I did some research and found nine different opinions.  As a builder I have always put support underneath unless the overhang is 6″ or less.  But since we want our contemporary kitchen to have as many clean lines as possible, I decided to go directly to the stone experts.  According to the Marble Institute of America, you can safely overhang granite that is 1- 1/4″ thick up to 10″ without supports.  However, the cantilevered portion cannot be more than 1/3 the total width of the countertop.  So, we are ok on the first criteria, but we exceed the 1/3 criteria by four inches.  So, we will need corbels or supports to keep the countertop from being in an unbalanced condition.

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Our Project

We have corbels on order, so for now, we have added some temporary brackets made of plywood.  Basically, a triangle and a rectangular flat piece is cut, glued and screwed together and then screwed to studs in the knee wall.   The rectangular piece that goes flat against the wall is cut two inches bigger than the thickness of the triangular piece so you have a surface to screw into.

Desks

What if you are spanning from cabinet to cabinet for a desk area or appliance?  What is the granite overhang limit in this case?  Well, according the Marble Institute of America, you can span up to 2′-0″ for 3/4″ thick granite and 3′-0″ for 1-1/4″ thick granite.  Just keep in mind, you will want to speak with your fabricator/supplier before making a final decision as he/she is more familiar with your particular type of stone.  Some stones are more brittle than others so the granite overhang is affected by the actual stone chosen.

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