How to Install an Interior Doorway Header
- 1). Measure the width of the opening where you will be installing the interior door to determine the width of your header. Run a tape measure from one side of the opening to the other and record the measurement. Most interior doors range in width from 24 to 30 inches.
- 2). Mark the desired length on the piece of lumber.
- 3). Line up the blade of a circular saw with the mark on the lumber and press the trigger. Hold the lumber in your nondominant hand and run the blade of the circular saw through the lumber. Measure the piece to verify the proper cut was made on the board.
- 4). Set the header piece into the opening above the door. Ask an assistant to hold it firmly in place, if necessary. Ensure it is level before hammering a 2-inch finishing nail directly in the center of the header. Measure 8 inches in each direction and insert a nails at those points.
- 5). Space the remaining nails every 8 inches. Hammer them so the head of the nail is flush with the header. Grip the header and verify it is secure before installing the door.
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