How to install a countertop in an unsquare corner

When remodelling a kitchen, it is common to discover that the walls are not perfectly straight. This becomes a problem during the installation of the cabinets and countertops when the deviations in the wall need to be corrected for so that the counter and cabinets look level and straight against the wall. After the cabinets are installed and levelled, the installed scribes the countertop and fits it to the unsquare walls through a process of sanding.

Turn a one-piece laminate countertop so that the back side of the upright backsplash area is facing you. At the top of the 4-inch backsplash is a horizontal edge that is about 1/2-inch thick. This is called a pine stick. If your countertop doesn't have a backsplash, you will be sanding and scribing the back edge of the counter itself.

Sand along the underside edge of the pine stick or back underside edge of the counter at a 45-degree angle so that the top laminated edge is untouched and the angle is toward the counter. This thins out the material along the scribed edge to make it easier to correct. Repeat this for both counters if your corner is already built.

Position build-up sticks along the top of the cabinets to the thickness of the cabinet installation blocking. Check that the counter is level in both directions. Press the countertop into the corner as much as possible. Set a pencil compass to 1/8-inch and scribe away from the corner in each direction so that a pencil line is drawn on the pine stick or top of the counter.

Sand at a 45-degree angle along the line. Check the fit and make small modifications until the counter fits snugly into the corner.

Use build-up sticks as necessary for your counter to be straight and level. Press the counter into good contact with the wall. Screw through the blocks in the cabinets and into the underside of the countertop. Do not screw through the counter.


Install the sink before final installation of the counter to make things easier. Also, add your end caps along the sides of the counter prior to installing the counter if your ends are tight.

Things You'll Need

  • Belt sander
  • Build-up sticks
  • Compass
  • Counter screws
  • Screwdriver
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About the Author

F.R.R. Mallory has been published since 1996, writing books, short stories, articles and essays. She has worked as an architect, restored cars, designed clothing, renovated homes and makes crafts. She is a graduate of the University of California at Berkeley with bachelor's degrees in psychology and English. Her fiction short story "Black Ice" recently won a National Space Society contest.