How to Install Countertops With a Mitered Edge

Spread a sheet on a hard and level surface. Place both precut countertop pieces facedown over the sheet.

Dry-fit both pieces to ensure the joint is seamless and smooth. Separate the two pieces and spread a thin layer of adhesive caulk over each mitered edge.

Join the glued edges of the pieces together and hold them together for several minutes to help the bond set.

Wipe excess glue that seeps through the joint with a wet rag. Set the joint piece facedown on the cushioned surface.

Slide an I-bolt into each slot along the mitered joint of the pieces. Use a wrench to tighten the screws in the bolts partway. The bolts pull the pieces together, forming a tight seam.

Check that the mitered corner is level, or tap the section that is slightly higher back into alignment. Lay a level over the mitered corner to ensure the joint is aligned and smooth before you tighten the screws on the bolts completely.

Allow the glue to dry for the time specified on the label directions. Once it dries, assign a helper to hold one end of the countertop while you hold the other. Center and lower the countertop over the cabinets carefully, without damaging the surface.

Assign the helper to hold the countertop firmly in place while you drill holes into the cabinet’s corner braces. Extend the holes into the lower side of the countertop, so the screws you insert anchor the assembly securely in place. However, avoid drilling the holes deeper than two-thirds of the countertop thickness, since otherwise the tips of the screws will be visible from above.

Drive 1 1/4-inch wood screws into the holes to secure the mitered-edged countertop to the cabinet.

Insert caulk into any gap between the countertop and the backsplash to keep moisture and debris from getting behind the countertop.