Finished granite slabs weigh about 13 pounds (5.9 kilograms) per square inch for the thinner size and 19 pounds (8.6 kilograms) per square inch for the thicker size. For an 8-foot (2.4-meter) slab of countertop that’s 3 centimeters thick, that’s about 150 pounds (68 kilograms).
Installing Granite Countertops
Whether you plan to have your granite countertops fabricated and installed or want to do some or most of the work yourself, the process is labor-intensive and requires meticulous measuring and skill.
If you're installing granite in a kitchen, pull out the stove and refrigerator and remove the sink from the existing countertop. If the old top was screwed on, empty the lower cabinets and pull out all drawers and doors. Pry off your old countertop. Then tape cardboard or paper over all cabinet fronts for protection [source: Larson].
Accurate measurements are crucial. Be sure to note details like appliance openings. Usually, these are sized precisely, so finished edges will need to be flush with the cabinet ends. Templates are helpful in calculating cuts for sinks and cook tops. The thickness of the backsplash needs to be accounted for as well, to ensure that elements like faucets will fit between the sink and the backsplash. You should use plastic sheeting or a vulcanized rubber paint-vapor barrier between the subcounter and the granite [source: Walton].
Most countertops will have at least one seam because the material typically comes in slabs that are less than 10 feet (3 meters) long. Whenever possible, seams should be made at well-supported areas of the cabinetry. Because there can be a slight difference in the thickness of two granite pieces, shims might be needed to ensure the tops are flush [source: Walton].
Silicone applied between the two slabs allows for expansion and contraction, and a special epoxy holds the granite in place. When the epoxy is joining two pieces of the countertop at a seam, it should be mixed with colored resin to blend in with the color of the granite. Use colored glue in any visible seams. You should also mix the resin with the caulking that secures the backsplash to the countertop [sources: Keidel, Marblemaster].
Fortunately, it's easier to maintain granite countertops than to install them. Learn everything about sealing granite countertops in the next section.