PAGE 6
ASTA AMERICA
Be positive about the accuracy of your level elevation reference marks!
FIGURE 6
LEVEL
REFERENCE
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3.
Procedure for shooting level reference marks
a.
Create level elevation marks at left and right jamb faces using a level reference device or
survey instrument as shown in Figure 6.
b.
Measure the distance from each level reference mark to the sill to determine if the sill is level.
If there is a difference in measurements from the marks to the sill,
the sill is not level. You must shim the wall angle with the longest
reference measurement to verify that both wall guides are
mounted to the same elevation.
4.
Procedure for installing wall angles
a.
Use a plumb bob or similar device to establish a true plumb reference.
b.
Install first wall angle plumb vertically at the correct elevation, and at the correct "W"
dimension sill mark.
c.
Install second wall angle by placing it at the "W" dimension marked on the sill at the
second jamb as shown in Figure 7. Shim if necessary.
