After you’ve scribed, trimmed, test fitted, and applied any end caps to the countertops, and the glue has set at any mitered corners, you can begin the job of securing your countertops to the base cabinets. Follow these steps to attach it:
Don’t start securing the countertop to the cabinets until the mitered joint has dried. Allow the glue to dry for at least four hours, or overnight if the weather is humid. It’s better to wait a little longer than to rush the job and have the seam break because the glue hasn’t set up. If the seam does break, you need to remove the old glue — a very difficult task — and start over.
Position the countertop pieces on the cabinets.
Apply a bead of silicone caulk or construction adhesive along the top edge of all the cabinet parts that support the countertop.
Tip up a straight countertop to apply the adhesive. Insert shims under a mitered countertop rather than trying to tip it up — doing so is easier and is less likely to break the glue joint. The caulk or adhesive will hold all the parts in place after it dries.
Lower the countertop back into place or remove the shims.
Place pressure sticks every 12 to 18 inches to help the adhesive bond the countertop to the cabinets at the back edge and apply clamps to the front edge.
Be sure to place pressure sticks along the back corners (where the corner blocks are located) to get the countertop down tight.
Seal any gap between the backsplash and the wall or along the edges and the wall with a clear silicone acrylic caulk.
Reinstall the cabinet doors, put the drawers back in place, and go have a beer.
If you’re going to paint the walls and you want to paint the clear caulk, make sure the label says that it can be painted! Most silicone acrylic caulk is paintable, whereas regular silicone caulk isn’t.