Cantilevering Some Granite
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Cantilevering Some GranitePosted by Derek at August 04. 2008
I want to use a 9 foot long piece of “cosmic” (black with white accents) granite on an existing 9 foot wide brick wall in a family room. I want it to be the mantle above the existing firebox, which is off-centered in the brick wall. I want granite to hang 8 inches off the wall (therefore, 9 ft. by 8 inches). It is 3 cm thick and I don’t want to see much support. Not sure about weight of this specific granite, but I think 3 cm is on average 20-25 lbs/sf. I would like to either use steel rods or steel “T” shapes and let them be exposed and then painted out. The T profile could be nice and then notch through the mortar joints of the brick. The existing brick wall has concrete block back-up. Does anyone have any suggestions what size steel to use and how to anchor to brick or back thru to the CMU? Maybe steel doesn't have to get back to CMU and have steel supports attached to steel plate and to brick with masonry bolts? Also what type of silicone/setting compound to attach the granite to steel support? I am assuming the required supports should be maximun 3 feet apart. Again, I’d rather not see brackets, but a cleaner look with simple steel supports directly below the granite and parallel to it. Any suggestions would be greatly appreciated. This is a very different question than typical kitchen island overhang issues.
Thanking anyone in advance.