1) There are several methods for accurately setting out and measuring angles on a construction site, including using a builders square, the 3:4:5 method, optical equipment, and satellite navigation. 2) Setting out a rectangular building involves establishing corner points and boundary lines, measuring lengths and checking for square corners using the building diagonals. 3) Temporary corner profiles are erected and marked with setting out lines to aid in transferring measurements underground once excavation is complete.

1. Contribute to Setting Out

2. Tutor Copy

3. SETTING OUT
For measuring when setting out, builders may use a 30
metre setting out tape.
The tape measure can be either made of fabric or metal.
With constant use and pulling the tape tight a fabric tape
could tend to stretch which could give an incorrect reading.
Wipe all tapes clean after use and to maintain a metal tape,
lightly lubricate it with oil

4. SETTING OUT A 90 DEGREE
ANGLE (SQUARE)
For ease of construction and to keep building costs to a
minimum the majority of buildings are made up of a collection of
squares and rectangles. Squares and rectangles all have
angles/corners at 90 degrees.
There are several ways to set out or check a right angle on site.

5. BUILDERS SQUARE
Never presume that the square is accurate. It may have been
made faulty or damaged through use or neglect.
To check a square for accuracy lay it on a flat surface and draw
round the 90 degree end. Totally reverse the square and place it on
the lines you have just drawn. If the square follows the lines, it is
accurate, if it shows different it is faulty.

6. 3:4:5 METHOD
This method is also known as Pythagoras. A triangle having
sides measuring 3m, 4m & 5m, creates a perfect 90 degree
angle, at the corner. By using this method builders are able to
set out a square corner using just a tape measure.
A B
C
3m
5m
90
degrees
4m

7. SETTING OUT OTHER ANGLES
90 degree angles, and other angles, can also be set out using
optical equipment, such as a Site Square or a Theodolite.
Nowadays it is quite commonplace to use equipment
incorporating a laser beam and setting out buildings can now
be achieved with the use of satellite navigation.

8. SET OUT A 45° / 135° ANGLE
(FROM POINT A)
EQUIPMENT REQUIRED =
STRAIGHT-EDGE / BUILDERS SQUARE
CHALK OR PENCIL / TAPE MEASURE.
1.EXTEND WALL LINE XA TO B.
2.MEASURE ANY DISTANCE FROM A
(600mm) TO FIND POINT B.
3.DRAW LINE BC AT 90° TO LINE XB (USE
BUILDERS SQUARE OR 3:4:5 METHOD)
4.MEASURE FROM B TO C (600mm) –
same distance as in Step 2.
5.JOIN POINTS A TO C.
6.LINE AC CREATES A 45° ANGLE WITH
LINE BX & ALSO CREATES A 135° AT THE
ANGLE AT CAX
SETTING OUT OTHER ANGLES
C
135° 45°
A
X
B
IN A SQUARE ALL THE
ANGLES ARE 90°.
BY DRAWING A LINE
FROM CORNER TO
CORNER THE ANGLES
HAVE BEEN HALVED.

9. SET OUT A 60° / 120° ANGLE
(FROM POINT A)
EQUIPMENT REQUIRED =
STRAIGHT-EDGE / CHALK OR PENCIL / TAPE MEASURE / TRAMMEL SET
COMPASS OR LINE
STEP 1
1. EXTEND LINE XA.
USING A COMPASS SET AT ANY DISTANCE ((600mm) OR A PIECE OF LINE
AND CHALK SCRIBE AN ARC TO CREATE POINT B.
STEP 1
1. EXTEND LINE XA.
USING A COMPASS SET AT ANY
DISTANCE ((600mm) OR A PIECE OF
LINE AND CHALK SCRIBE AN ARC TO
CREATE POINT B.
X
A
C
B

10. STEP 2
PLACE COMPASS POINT ON B, WITH COMPASS SET TO SAME
DISTANCE, AND SCRIBE AN ARC, INTERSECTING THE PREVIOUS
ARC TO CREATE POINT C
X BA

11. STEP 3
DRAW A LINE FROM A TO C. THIS LINE CREATES A 60° & A 120°
ANGLE TO THE BASE LINE
BY JOINING B TO C CREATES AN EQUILATERAL TRIANGLE. THIS
SHAPE HAS ALL 3 ANGLES EQUAL
TO 60°
120° 60°
BAX
C

12. THE BUILDING LINE
This is an ‘imaginary’ line, determined by the Local Authority Highways
Department. This line is usually a measurement taken back from a
point on the highway – maybe the centre of the nearest road, the kerb
line of the pavement, or a manhole in the roadway.
Its’ function is for any possible future road widening; therefore to
make sure that any new construction will be far enough back from the
highway. Any infringement of this measurement could result in fines
or legal proceedings to remove any construction in front of this set
measurement.
Contacting the Highways Dept. will position this line. Consider that if
the construction faces more than one roadway, there could be more
than one Building Line measurement required.

13. ROADWAY
KERB
LINE
MEASURED
BACK FROM
KERB LINE
BUILDING
LINE
No permanent part of the construction may overstep the Building Line. You
may build up to the Building Line, behind it, but NOT INFRONT of it.
THE BUILDING LINE

14. SETTING OUT A RECTANGULAR
BUILDING
Setting out is required to locate the position of a building on the
ground. The setting out determines the positions of the walls,
which in turn determine where the ground is to be excavated and
the concrete poured, to create the foundation trenches.
EQUIPMENT REQUIRED:-
DRAWING / 30M TAPE / 3M TAPE/ STEEL SETTING
OUT PINS / LUMP HAMMER

15. STEP 1
AFTER DETERMINING THE
POSITION OF THE BUILDING
LINE, SET OUT USING
STEEL PINS AND BUILDING
LINE TO POSITION THE
FRONTAGE LINE (AB) OF
THE NEW BUILDING
STEP 2
DETERMINE ONE OF THE
FRONT CORNERS (A) AND
SET LINE (AC), SQUARE TO
THE FRONTAGE LINE.
FRONTAGE LINE
C
A
B
D
STEP 3
MEASURE THE LENGTH OF
THE BUILDING ( A – B)
AND ESTABLISH POINT B.
STEP 4
ERECT LINE BD, MAKING
SURE THE ANGLE AT B IS
90 DEGREES.
C
A

16. CHECKING THE DIAGONALS
STEP 5
MEASURE THE WIDTH OF
THE BUILDING, A-C & B-D.
POSITION A LINE FROM
THESE 2 POINTS TO
COMPLETE THE
RECTANGLE.
D
C
B
A
STEP 6
TAKE A MEASUREMENT
FROM CORNER TO CORNER
(A - D & B - C). WHATEVER
A – D MEASURES THEN
B – C MUST MEASURE THE
SAME. IF BOTH
DIMENSIONS ARE THE SAME
THAT MEANS THAT EACH
CORNER IS PERFECTLY
SQUARE. IF DIMENSIONS
DIFFER THEN THE SETTING
OUT PROCESS MUST BE RE-
CHECKED FOR FAULTS.
STEP 7
AS A FINAL CHECK,
RE-CHECK ALL THE
DIMENSIONS FOR
ACCURACY
DC
BA

17. The next process is to erect CORNER PROFILES, set back from each corner.
As shown above, timber pegs are driven into the ground and a timber profile board
nailed across.
SETTING
OUT LINE
PROFILE
BOARD SIZE
APPROX.
75mm x 30mm
TIMBER PEGS APPROX.
50mm x 50mm
STEEL
SETTING
OUT PIN
SETTING
OUT LINE

18. CORNER PROFILES
Because the steel setting out pins will need to be removed for
excavation of the building, each timber corner profile, because it is set
back, can remain in position whilst the building foundations are
removed/excavated.
The setting out lines are extended from the steel setting out pins and the
positions of each line marked onto the profile board. When the
bricklayer begins to set out the external walls he/she can attach the lines
onto the relevant marks, without the need for having to set out the
building again.

19. THE POSITIONING OF SETTING OUT
PROFILES FOR A TYPICAL BUILDING
The setting out profiles are set back from the building so that they will
not get hit by machinery working on the excavation. If excavation was
to be carried out by hand the profiles could be positioned closer to the
works.

20. When the foundation concrete has set the original setting out lines are fastened to
the setting out profiles, once again.
The bricklayer now needs to transfer the lines positions onto the concrete
foundation.
This is achieved by carefully plumbing down where the lines travel and marking this
onto the concrete. These marks represent the positions of the walls from above
ground to below ground.
LINES PLUMBED DOWN AND POSITIONS
MARKED ON TO THIN SMEAR OF MORTAR.
BRICKWORK CAN THEN BE SET OUT, BELOW
GROUND LEVEL, IN THE CORRECT POSITION.

21. LEVELLING
Initially all four corners of a building will have to be built up to the same level.
This is usually firstly achieved for the horizontal damp proof level, which is generally 150 mm, above finished
ground level.
All buildings have a levelling DATUM point. This datum would be shown on the working drawing and it is quite
often the ground floor finished floor level, shown as F.F.L. More often than not this level is usually the same as
the D.P.C. level.
To find the F.F.L. / D.P.C. level of a proposed new building it may be necessary to transfer a level from a datum
elsewhere, possibly a long way away. This would be one of the first tasks to be done on a construction site and a
surveyor would set up the SITE DATUM or TEMPORARY BENCH MARK.

22. site datum or temporary bench mark is a point
where all levels, either above ground, or below
ground are initially taken from. can be a length
of steel angle iron set firmly into the ground
and surrounded by concrete. to protect the
datum from damage, by plant, it would be
positioned away from activities and
surrounded by a fence.
Symbol relating to a datum point

23. For greater distances more accurate devices
are required, such as :-
DUMPY LEVEL
QUICK SET LEVEL
TILTING LEVEL (AUTOMATIC)
THEODOLITE
LASER LEVEL