How to Brace Plywood Doors

Measure 5 inches from the top interior of the door and make a small pencil mark. Find the center of the door, then measure 5 inches from the bottom of the door. Make a mark in both locations.

Find the width of your door and reduce the measurement by 2 inches. Cut three 2-by-4 planks to the recorded measurement.

Place the center of one 2-by-4 plank on the pencil mark 5 inches below the door, and then attach the plank to the door with nails and a hammer. Repeat this step by attaching another plank on the center marking. Attach the last plank to the marking 5 inches from the bottom of the door.

Measure the distance from the bottom hinge corner of the middle plank to the opposite bottom corner of the top plank. The hinge corner is the side of the door where the hinges are located. Measure the distance from the bottom hinge corner of the lower plank to the opposite bottom corner of the middle plank. Cut a 2-by-4 plank to each measurement.

Cut the corners of both 2-by-4 planks to a 45-degree angle. Affix one of the 2-by-4 planks diagonally from the bottom hinge corner of the middle plank to the opposite bottom corner of the top plank. Affix the remaining 2-by-4 diagonally from the bottom hinge corner of the lower plank to the opposite bottom corner of the middle plank. Use nails and a hammer.