Supporting Granite With Corbels
Tom,
We just had 3cm granite tops installed in our home. I see from the other questions that its acceptable to place these directly on countertops with no plywood underneath so that answers one question. The thing i’m worried about is my raised bar with 18″ overhang. The corbels i had purchased to support the weight were only 6 1/2 inches deep and my installers said they didn’t think it would be enough support. Is there a formula to determine how long your Corbels should be or could you recommend what you would use. I’ve found some affordable 3 x 9 x 12 ones online and might try those if you give me the ok. Another thing that concerns me is that the only thing used to hold the granite to the raised kneewall was a silicone type epoxy. Is this normal? I would think it would need some kind of support bracket or screws on the inside of the raised bar as well as the outside support of the Corbels. Let me know please so i know which direction to go.
Thank you,
Brian
Hello Brian,
This is a tough one to answer without seeing it. I don’t know a few important details. For starters, are the corbels that you are considering made of steel or wood? If steel, then 9″x12×3″wide corbels are plenty strong enough but they are only as strong as the backing they are anchored too. For 3cm granite, you need to consider that the weight is about 18 pounds per square foot so you’ve got a weighty overhang to consider. If your corbels are secured in place then a strong silicone like Dow Corning 795 would be fine to glue it down. Don’t rely on silicone to provide any dead-load support. However, it will maintain the lateral security of the top.
Basically, after your corbels are in place at about 24″ on-center for 3cm granite, just see if they will hold your body weight (or around 160 pounds).
I am sorry that I can not be more specific because there are a few variables here that once should actually inspect first hand.
Best wishes,
Tom Cordova
January 21st, 2007 at 5:55 pm
We we are in the process of remodeling our kitchen. Our cabinets are a honey oak and we would like to use granite on our countertops. We are not sure if we want to go a light color or dark color granite. We will be selecting stainless steel appliances and our flooring is taupe color 12X12 tiles and will be painting our walls a light beige color. We are interesting in the brown/black/beige colors. Can you make some suggestions as to granite that might compliment our cabinets/color scheme.
Thank you,
Darrell
May 30th, 2007 at 11:19 am
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