Step 1 Set Stair Measurement on Square
Lay the framing square on the stringer board so the unit run measurement on the outside of the wide body of the square intersects the edge of the board. Clamp a stair gauge on the inside edge of the leg so it won’t interfere with the marking. Set the length of the unit rise on the outer edge of the narrow leg so it intersects the edge of the board. Clamp on a stair gauge to hold the measurement. Mark the rise and the run for the first step at the top end of the stringer. Place the framing square on the board for the stringer with the gauges resting against what will be the top edge. Intersect the corner of the board with the rise line. The rise measurement at the top end of the stringer sets the stringer at the correct distance from the decking surface.