How to build a corner bench seat

Updated February 21, 2017

A corner bench seat provides a convenient extra seat that is particularly useful in small spaces. Because the bench is going in the corner, it can be mounted to the wall. The bench seat will consist of a triangular frame and a plywood seating surface. The side pieces of the frame get bolted into the wall with carriage bolts for a sturdy simple seat design. The space underneath the bench seat can be used to store items in a small round basket.

Measure up 18 inches from the corner in the wall where the bench seat will be located. Mark the wall at this height. The top edge of the seat support frame will be at this height. Use a stud finder to locate the studs in the wall. Mark the locations of the studs.

Cut a 45-degree angle on one end of the 2-by-4-by-16-inch board and a 22-1/2-degree angle on the opposite end. Make the cuts on the mitre saw with the 4-by-16-inch side of the board lying flat on the mitre saw table. The angles should be on one side and if you follow the lines of the mitres they would intersect. The side opposite the angles should still measure 16 inches long. These are the side support frame boards.

Position the two side support frame boards with the 4-by-16-inch side flat against the wall so that the top edge is on the 18-inch measurement marks. The 45-degree ends of the board should be on the inside of the corner joint so that they meet up flush to match with the 90-degree angle of the corner.

Fasten the side support frame boards in place by driving a carriage bolt through the support boards into the wall where the stud markings are located. Use two bolts per support board. Place a level across the boards to verify that the supports are level prior to tightening the bolts completely. Tighten the bolts once level.

Cut a 22-1/2-degree angle on both ends of the 2-by-4-by-23-inch board with one 4-by-23-inch side lying flat against the mitre saw table. The angles should intersect if you followed their lines. The side against the table will still measure 23 inches long.

Align the front support board with the angles facing toward the corner so that it matches up with the side supports. Drive two flush trim wood screws per joint through the front support into the ends of the side supports.

Draw a triangle on the plywood panel by measuring 16 inches in both directions at one corner. Mark the measurements and connect the marks with a straight line across the panel. Use a pencil and straight edge to make an accurate triangle.

Cut across the line using a circular saw. Sand the plywood panel with a progression of medium- and fine-grit sandpaper until the panel is completely smooth. This is the seat panel.

Slide the seat into place on top of the supports. Fasten the seat in place by driving flush trim screws through the seat into the supports every 3 inches.

Fill the screw holes with wood filler and a putty knife. Allow the filler to dry. Sand the filler until it is smooth with the surface of the wood.

Apply a wood finish to the seat. Allow the finish to dry before use.


Place a circular wicker basket underneath the seat to organise small items.


Wear eye protection while working with wood.

Things You'll Need

  • Tape measure
  • Pencil
  • Stud finder
  • 2 boards, 2-by-4-inch, 16 inches long
  • Mitre saw
  • 4 carriage bolts
  • Screw gun
  • Bolt driver bit
  • Level
  • Board, 2-by-4-inch, 23 inches long
  • Box, flush trim wood screws
  • Plywood, 3/4-by-23-by-23-inch panel
  • Straight edge
  • Circular saw
  • Wood filler
  • Putty knife
  • Wood finish
  • Paintbrush
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About the Author

Jonah Morrissey has been writing for print and online publications since 2000. He began his career as a staff reporter/photographer for a weekly newspaper in upstate New York. Morrissey specializes in topics related to home-and-garden projects, green living and small business. He graduated from Saint Michael's College, earning a B.A. in political science with a minor in journalism and mass communications.