stairs steeper, the riser should not exceed 8 inches. To make the stairs steeper, increase the rise and

shorten the run (see Figure 2-37).

Rule 1. The sum of 2 risers and 1 tread should equal 25 inches.

Rule 2. The sum of 1 riser and 1 tread should equal 17 to 19 inches.

Rule 3. The height of the riser, multiplied by the width of the tread, should equal approximately 75

inches. According to rule 1, a riser of 7 1/2 inches would require a tread of 10 inches. A 6 1/2-inch

riser would require a 12-inch tread.

first divide the total rise by 7. If the total rise for a stairway is 7 feet 10 inches or 94 inches, the answer

will be 13.43. Since there must be a whole number for risers, select the one closest to 13.43 (13) and

divide it into the total rise.

94 inches divided by 13 = 7.23 or 7 l/4 inches

Number of riser = 13

Riser height = 7 1/4 inches