Installing a granite top on a vanity cabinet can provide a bathroom design with a clean, modern look. Granite vanity tops are durable, beautiful, and have the added benefit of being able to be used with an undermount sink. Installing a granite vanity top can be done after the sink and faucet have been attached to the top, and the cabinet base is clean.
 

1
Turn the granite counter upside down so that the underside is face up. Attach the sink to the underside of the counter by applying a bead of silicone adhesive to the underside of the counter around the rim of the sink cutout. Press the sink into the adhesive, so that the sink's opening matches up with the granite cutout.
 

2
Using epoxy, attach the sink's mounting hardware to the sink and counter. This is done in three steps. The bolt stems must be fixed to the granite, the mounting clips themselves to the sink, and then the two will need to be connected together by use of a nut and wrench. Apply epoxy to the underside of the granite and press the bolt stems into place. Allow the epoxy to set up for 10 minutes, then use the epoxy to attach the mounting clips to the sink. Use the wrench to attach the mounting clips to the bolt stems. Allow the epoxy and silicone to set for 24 hours.
 

3
Install the faucet onto the vanity top by unscrewing the decorative portion of the faucet from its stem, pushing the stem of the faucet through the faucet holes drilled in the counter, and tightening the top back on. Use the wrench to secure the connections. The water supplies and drain will be installed after the vanity top is secure. To avoid chipping the sink, keep the vanity top upside down for this step.
 

4
Place the granite vanity top on the base cabinet to check placement. The top should extend by 1 inch on each side and to the front of the cabinet. Many counters are templated and fabricated to fit the exact vanity and location. This will take into account wall slants and angles. If a template has not been taken, try to place the counter as close to the center of the vanity and as square as possible. If need be, a color matched caulk can fill any gaps where the wall is out of plumb, or a backsplash can be installed over the gap.
 

5
Remove the granite top from the vanity after testing the fit and apply a bead of silicone adhesive to the sink cabinet's rim. Place the granite top back on the vanity cabinet and wiggle it slightly into place to achieve a good bond with the adhesive. Allow the adhesive to set for 24 hours before hooking up water supplies and drains.