We are building a home on a hillside. The lower level has an apartment with two french doors off the great room which opens to the water view. Before the house was built and going by the architectural drawings it appeared that those doors would open to a ground level deck or patio. Now that the house is all poured in reality those doors open to a drop of about 20 to 30 feet. We would like to put cantilevered balcony along the front of the two doors. The length of the balcony would be about 26 feet and the depth from the house 3 1/2 feet. This would be enough for the french doors to open completely. The supports would be fastened to the concrete wall. How many supports would be needed for this expanse. Could the floor of the balcony support the same marble we have inside. Is there plans available for this or a site we can reference. A search of the forums didn't result in much information. Thanks in advance.

AJ