How to Install Granite Countertops
In this project, expert stone masons Derek Stearns and Dean Marsico use a system of granite pieces to simulate the look of slab granite
After cabinets are installed, it’s time to measure for the granite countertops. It’s wise to be very precise.
In this project a do-it-yourself granite countertop service provides the granite countertops, a modular system that eliminates expensive fabrication. The granite system requires sheets of ¾” plywood be laid on top of the cabinets to support the granite.
Granite comes in a myriad styles and choices. Personal selection depends on a variety of factors including overall design and style of the kitchen, color and type of cabinets and flooring, local availability of granite, individual taste and more.
Be sure to note how much you want your countertop to overhang the face frames of the cabinets, typically 1" to 1 1/2". Also note which edges of the counter should have a bull-nose or other style of finished edge.
Allow 3 to 4 weeks, and sometimes longer, for delivery. If one chooses to go with a granite fabricator, the fabricator will commonly want to do its own measurements and installation to insure precise fitting.
Cut 3/4" plywood to fit on top of all the base cabinets. The plywood supports the granite and gives enough clearance for the bull-nose edging to clear the drawers and doors.
Make sure the plywood does not overhang the outside dimension of the cabinet.
To attach the plywood to the frame of the cabinets with screws, first drill a pilot hole to keep from splitting the hardwood face frame. Make sure to center the screws into the frames underneath.
You'll need help working with granite slabs. Some of the slabs alone can weigh more than 200 pounds. Granite slabs can also be brittle, so handle them with utmost care.
Be sure to have space set aside to store the slabs before installation. It's best to store them as upright as possible, be careful to not let them "domino" and break.
Your walls may not be perfectly square, so it's a great idea to create a template for the granite countertops. Use kraft paper (or a stiffer material) to make a template of the actual measurement of the countertop. (A template is easier to move around than making marks on a granite slab.)
If you need to scribe a slab to fit, apply duct tape to the base of the saw to protect the granite.
Use a circular saw with a dry-cut segmented diamond blade.
Test fit pieces that are cut, and be careful with long, thin pieces that could snap.
Set granite in place for the sink counter, and trace the exact line around the opening for the sink onto the plywood subcounter.
Remove the granite slabs that were dry-fitted only.
Use a spade bit to make a pilot hole in the plywood, and use a jigsaw to cut the sink hole. Make it about 1/8" larger than the line you drew.
Drop in the sink.
Before you lay the granite slabs back on top, lay down some cardboard to protect the sink overnight. You'll remove the cardboard before joining the granite seams.
Level the seams for the slabs.
Use 1-1/4" screws to adjust the height of the slab from underneath to raise and lower the countertop.
Use a level to fine tune as tips of screws push from the underside of the slab.
With others helping, lift the granite and put half-dollar dollops of silicone around the perimeter of the cabinets (space about every 6" to 12").
Place a bead of caulk around the sink rim.
Apply second bead on top of sink rim to waterproof the gap between the sink and the countertop.
Lower the granite slab gently back down.
Tape over seam with blue masking tape.
Next, to fill in the seams you'll start with a dollop of polyester-based resin and add a small amount of color, trying to match the color of the granite.
Mix with a putty knife.
Keep checking color against the stone.
Create a few different colors to blend into the seam.
Add the hardener (3 percent hardener to 97 percent resin), and mix only a workable amount as you only have about five minutes to apply.
Apply a base-coat of neutral color mix into seam.
Dab in and smooth as you go.
Apply a little lighter color here and there.
Apply the darkest color last.
As soon as you're done, pull off the masking tape so it doesn't dry on the tape.
After it's dried, about 30 minutes, smooth it out with a seam stone.
Use slow speed, and firm pressure.
Keep the stone moving in small circles, you'll feel when it's smooth.