Setting out of building
As simple as setting out of a building may look majority of us do not bother to find out what it is all about
Setting out is simply the physical transfer into the ground what was initially on plan or in paperwork. Transfering the building professionals drawing (the architect) plan onto the ground is a process of setting out.
Setting out can be complex yet simple. For more accurate transfer some engineers uses the services of land surveyors to get their set out right especially in large projects. Theodolite is often used by the surveyor or any engineer that has a good knowledge of the application to get the level of a subject place in relation to a decided point around the building area.
But we are going to concern ourselves with the simple pegging which is common and later talk about setting out with using blocks.
Assuming you have a rectangular site of 50ft x100ft what you should take note first of is the four corners where we have your pillars. Put pegs at each points or very close in case you have disturbing concrete . After establishing these four corners put nails on top of each peg and then run rope round the 4 pegs.
Of course I need to tell you that you will get peg and thin wood (or tie rod] from the sawmills (the number required has been worked in your free sample estimate you get when you subscribed for my articles )
Next is to establish a point by measuring out a setback from fence to your building line. Taking just one side measure the setback from back of fence to the end of building lines in that particular angle, then come to the front and measure the setback also as given on your drawing plan .
After this go back to the rear or you may use the front as a point mark depending on which setback is more important to you in case the survey plan did not tally with what is the actual measurement on ground.
Measure the setback from fence establish this two points with pegs then put a rope to cross both pegs and make them form a right angle or 90 degrees , this is necessary because of it ease and most drawings are drawn to follow straight right angles. To determine if your rope are at right angle put a checker popularly called ‘square’ by bricklayers, this will direct you if you need to shift the other rope that can be varied since one is already fixed to form a base mark( i.e the rope running through two pegs from the rear to the front either on left side or the right side.
After establishing a right angle, do your measurement to correspond with what is on plan and then use the square at the other end to now establish the other two points. When establishing these points be conscious to place your peg at 1m or 3 ½ ft behind your building line i.e where blocks will actually pass through.
After this, nails peg at 3m interval round under the rope marking your building line, then nail tie rods (flat thin wood) on top round the entire area.
You are ready to start measuring and transferring what is on plan to the profile boards (flat thin wood on top of pegs) establish each room measurement by nails ( you require four nails at each measurement, two to establish the two sides of block you are going to place later on then the other two at both ends to serve as the points where you will excavate ,the length of this is usually three times the width of the block you are using that is if you are using a 6“ block then expect to excavate or dig a trench of 18” wide.
The type of digging also depends on the type of foundation recommended by your structural engineer.
Establish the depth based also on recommendation and you are ready to cast your concrete. After casting of foundation, use the nails on your profile board to determine where your blocks will follow from ground to complete foundation courses (note this is variation of application in raft and more complex foundation where reinforcements and concrete will be applied more.
Set your blocks 3,4 or more coaches / courses/ layers as recommended before casting your ground floor slab or oversite concrete or german floor.