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Installing Granite With An Overhang

Tom,

We are in the process of replacing our solid surface counter tops with granite. On the breakfast bar the granite will have a 12″ overhang. The granite fabricator recommended that we install corbels for support. What is the best way to install the corbels to ensure that they will support the granite overhang? Is there more than one way to install the corbels?

Thank you,
Carl Wallace

Hello Carl,

I have to make a couple assumptions because you did not provide me with some important information. For the purpose of this reply, I will assume that the granite is 3cm solid stock and the granite color is not in Class D, meaning that it does not have fiberglass mesh on the back to keep give it strength.

Now then, there is some debate about how far 3cm granite should overhang without corbels. If you consider that children might hang or pull on the granite overhang or that someone might sit on it, then you should install corbel at overhangs greater than 10″. If you have Class D granite, install overhangs past 6″. In general, Granite that is solid 3cm stock does not need corbels for flexural strength at 10″. Some granites, like the ones from Saudi Arabia, do not need it at 12″. However, my comments are regarding flexural strength issues and do not apply to safety concerns. Installing corbels is important for the child safely reason mentioned above so if you can live with the knee bangs, then you should install them as follows.

Start 6″ in from the open end, and put one corbel there. Do the same on the other end, unless the counter meets a wall, in which case you should install it against the wall. Then install corbels equally apart between the two outside corbels without exceeding 30″ between any two corbels. For 3cm thick granite at 12″ overhang, I would suggest 6″x6″x 1 1/2″ wood corbels or 6″x6″x 3/4″ steel corbels. Note, you can vary from this advice slightly depending on your exact cabinet dimensions. Just use good common sense.

Best wishes,
Tom Cordova

This entry was posted on Monday, September 18th, 2006 at 10:35 am and is filed under Answers to Granite Questions..., Installation Issues. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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7 Questions Recently Posted:


  1. June 27th, 2008 at 3:18 am

    Hi – I have a granite counter with a 10.5″ overhang. It was installed prior to purchasing the corbels. I need to install the corbels, but because of the keyslot design for the mounting hardware on the back of the corbels, if I put a screen into the back of the counter cabinets, and then install the corbels, the corbels will be 1/2″ from the underside of the granite – a pretty large gap. How do I install corbels on an existing counter and avoid the gap?

    Bryan


  2. September 18th, 2008 at 6:38 am

    Hi,
    We are purchasing granite for an island 96″x42″ with 24″ deep run of cabinets on the one side and an overhang of 16″ and are not sure if we can just use 2 3 1/2″ square at the top maple legs at either end with some frame between or need corbels in the center, or how big the cross frame needs to be or how deep the corbels must be. the granite is Prado of standard 1 1/4″ thick not sure about the fiberlagss mesh, and no kids to sit on it around. Thanks , Ted


  3. November 11th, 2008 at 8:06 pm

    I just read this entry regarding the need for corbels with a granite overhang. I have the same question regarding mine: the overhang is 12″ with a length of about 110″. The granite is 2cm Golden Ray which I believe is grade D (but might be C). Nobody will be sitting or hanging on it. Your advice woudl be aprpeciated!

    Thank You


  4. December 16th, 2008 at 9:18 am

    Is there any publication stating industry standards for high bar overhangs?
    What is the minimum overhang requirement to install corbels for an island or highbar with a 2″x4″ knee wall for a support (high bar only)?


  5. March 2nd, 2009 at 8:34 am

    We have two base cabinets 27″ wide with “pot and pans drawers” made of solid 3/4″ plywood separated by 18″ for shelving and a 4×8 sheet of plywood on top. This makes for an overhang of 12″ on each side and 10 1/2 on the ends. We plan to install granite tiles on top with a oak trim on edges/sides. Do we need anymore support, some say no, others say yes. the tile is I think 3/8″ thick. The island is 36″ tall without the tile.


  6. July 28th, 2009 at 10:50 am

    I’m just wondering how to properly attach the steel support brackets to the granite counter overhang? I was going to simply screw in the bracket to the cabinet and let the counter rest on the bracket. The other method I considered is to use construction adhesive to glue them to the counter and to the cabinet base.

    Please advise – many thanks.


  7. January 30th, 2010 at 7:19 pm

    I have a breakfast bar. The bar is attached to the wall.

    I have a over hang on both sides about 19 inches .
    I bought two corbels. 12 and 1/4 long,and 8 inches wide.

    Is this going to work. Or do i need something else. And if it does

    work how do i install the key hole corbels to the wall.

    Shirley