9
Building Site Layout
B = 4 ft.
A = 3 ft.
C = 5 ft.
90°
B = 4'
A = 3'
C = 5'
Adjust corner stakes
together until diagonals
are equal.
Tip:
An orange masons
line is easier to see.
20' or 24'
#1
#1
#2
#2
#3
#3
#4
Temporary stakes
24" Min.
Masons line
1
90°
90°
#1
#2
#3
#4
#1
#2
20' or 24'
(verify)
Masons line
Same dimension used in S
tep #2
B = 4'
A = 3'
C = 5'
Dimension based on FieldPro length ordered
Masons line
2
3
4
Place a stake at point #4. Attach a masons line
from stake #1 to stake #4. Use the 3 • 4 • 5
Triangle Method to square up the corner
at stake #1 to establish a 90° corner.
Attach a masons line from Stake #3
to Stake #4. Make sure all lines are
level. Verify that both corner-to-corner
measurements are the same.
Adjust Stakes #3 and #4 in unison
until both diagonal measurements
are the same.
Equal
Equal
Drive in the first stake at point #1. Depending on which FieldPro
model you have ordered, measure over 20' or 24' and drive in
a second stake at point #2. Attach a twisted masons line between
stakes #1 and #2 approximately 12" above ground. Use a line level
to level the masons line.
Based on the length of the FieldPro you have
ordered, place a stake at point #3. Attach a masons
line from Stake #2 to stake #3. Use the 3 • 4 • 5
Triangle Method to square up the corner at stake
#2 to establish a 90° corner.
Using the 3:4:5 Triangle Method to “Square Up” Your Building Site
The “3:4:5 Triangle Method” of laying out a building site produces 90º
corners as shown in the diagram. It forces your foundation layout to
be a perfect rectangle instead of a parallelogram. To verify if a corner
is 90°, place a mark on the masons line 3 feet from the corner.
Place another mark on the adjacent masons line 4 feet from the corner.
The distance from the 3 ft. mark to the 4 ft. mark should be exactly 5 ft.
