For 3cm granite countertops the span between two supports (i.e. between two cabinets) where there would be no support between those to objects should not exceed 3 feet. For overhangs the extension past the support should be no more than 10 inches. These 10 inches should not exceed 1/3 the width of the suported section of the countertop. Lengths beyond 10 inches will require bracket or similar supports beneath the 3cm stone.

It is recommended that no extensive amount of weight be put on an a granite countertops overhang or spanned area.