Adjusting Hole Locations for Percent of Grade

When the invert elevation is specified for the centerline of the structure and the slope is specified as percent of grade, STACK-IT will determine the correct amount to shift hole locations. This takes into account the distance from the center of the structure to the wall and the slope of the grade.

The fundamental relationships are illustrated to the right in Figure 1.

To have STACK-IT automatically compute the effects of the grade, enter the elevations (on the Build screen) using the "@" to indicate the grade as shown below.

Invert 1 slopes down away from the structure at a 10% grade. Invert 2 slopes up away from the structure at a 10% grade. (See Figure 2.)

The Stack screen results show that the difference between the holes (in a 48" structure) is the correct 4.8". (See Figure 3.)