Setting out is the process of developing the physical positions of corners and walls of a building, and it’s done by transferring dimensions from the layout plan. Setting out clearly defines the outline of the excavations and the centre line of the walls, so that the construction can be carried out according to the plan.
A building is set out in order to accurately define the outline and width of the excavation and to determine the center line of the proposed building walls, so that construction according to the building professionals drawing (the architectural plan) plan can be transfer into the ground, this building process is called setting out of building. The center line method of setting out is generally preferred and adopted.
Setting out can be a very complex engineering process but with need experience its quite easy. Experienced engineer and surveyors are those involved in setting out of structures, in large projects, services of land surveyors are required for more accurate transfer of levels and angles in setting out with the aid of a Theodolite to decides points around the building area.
We are going to concern ourselves with the most common setting out method
- Setting out using pegging
- Setting out using blocks.
Errors should be avoided because the whole structure will be build based on the respective setting out.
While setting out, you must fulfill the following requirements
- Actual Length.
- Actual Angle.
Follow the Steps Below in Setting Out a Building:
 SITE CLEARANCE
This is the First thing you must do while Setting out a Building, It involves removing machinery and hazardous substances from a site, as well as levelling and preparing land for any planned construction or landscaping. Proper site clearance is essential for the safety of all workers and anyone else that may be present onsite.
 OBTAIN THE ARCHITECTURAL AND THE STRUCTURAL PLAN
These Plans are the Most important Drawing you must get before you start setting out your Building. The Architectural Plan will give you an insight on how your Building will Look like and help you in Establishing your Parallel Line.
The Structural Plan will Assist you in determining the Width of your Foundation, Depth of Foundation and the Exact Point to Put each of the foundation. The Structural Plan also give an Insight on Central Point of the Structural Walls and Columns.
 GET YOUR MATERIALS READY
Make sure you Get the necessary materials ready before you start. The Following Materials are needed for Setting out:
- Rope or line
- Marking tool etc
 ESTABLISH A PARALLEL LINE
The first thing to establish is a parallel line, in other to form a Parallel Line, their must be an existing building close to the proposed new structure or a particular Fence on any Static Structure that can be make reference to in Establishing our Line. These lines should be off-set from the building or Fence to prevent any possible snagging of the string lines. This line should then be established with the use of a stake at each end and the line should be fixed at each point. Please ensure the line is very tight as this will prevent a false reading if the weather conditions are very windy.
From the Diagram Above, In other to Establish a Parallel Line for the Detached House we need 2 Measuring Tape and 3 People. The First Tape will be use to Measure 7200mm from Edge of the Fence to the First Point of the House involving 2 People. The third person will Hold the Second Tape at a Distance of 6150mm away from edge of the Fence Forming a Distance of 3825mm From Same Point of the Building. The Person Holding the 2 tape must make sure the tapes are at the specify Distance, then he or she Mark with a Peg to form our First Point.
The Second Point will be Determine by Measuring 10020mm away from the First Point then making sure the Second Point is also 3825mm away from the Fence as shown in the Diagram Above. With these, you have form a parallel Line.
 USE THE 3 4 5 METHOD
The 3 4 5 method is an accurate method use in Getting the Exact Square of a Plan instead of Using the Engineering Square which may not be accurate for a Longer Span.
The 3 4 5 method is an application of the Pythagoras Theorem. i.e Forming right Angle. Most times, 2 or 3 people are involve in this. 3 meters is Measure from the Parallel Line created, then 4 Meter Away from the First point forming a Right Angle, you use your Measuring tape to Confirm the distance between the 3m point noted at the parallel line and the 4m noted at the other line is 5m. Note that your Parallel line remain The same, you only shift the other line to form the right Angle.
You repeat the same process for the Second Point Too.
 ESTABLISH YOUR PROFILES
Now we have 4 pins in the ground establishing the outside of our dig. The next thing we need now is to set up our profiles, these should be about 1000mm away from our 4 pins, make sure these extension are all the same and accurate. You make use of your Wooden Peg in Forming all this extensions.
 NAIL THE POINTS OF EXCAVATION ON YOUR PROFILE
Extend and Plumb up your lines and mark the line on top of your profiles and put in a nail and write on the profile something like “outside of dig” from this point we can mark the centre of our dig, which will also be the centre of our structural wall. As we know this measurement we can then establish on the profile our actual building line, i would write this on the profile “outside structural wall” and the inside. Put in small nails and repeat this on on each partition of the Building.
Put in your Line then Excavate where necessary according to our Structural Drawing and make sure your Excavations are all Levelled
 NAIL THE POINTS OF COLUMN ON YOUR PROFILE
When you are done with your excavations, the next things is to remove your Line and Nail another points to establish our columns. If you are using Out to Out, make sure you use it all through and if you are Using In to In, Use it All through.
Your Column Placement will be where your lines intercept each other. Make sure you make use of Spirit level while Placing your Columns.