Setting out a building: Step 1.
With pegs and string, carefully measure out the size of house, putting a peg in the ground on each of the four corners.
Setting out a building: Step 2.
To get the first corner in a building, put a peg in the ground and attach a piece of string. Stretch the string in a straight line, running parallel to the boundary line, for 3 meters. Put another peg in the ground at 3 meters and attach the string. Attach another piece of string to the first peg and stretch it 4 meters.
Setting out a building: Step 3.
Check if the corner is perfectly square. When the diagonal measurement between the 3-meter peg and the 4-meter peg is 5 meters you have a square corner to start from. (See diagram below)
Setting out a building: Step 4.
To make sure that the house is perfectly square, take a diagonal measurement across the house area, from one corner to the other, and then take another measurement between the other two corners, forming a cross. If these measurements are not the same, you will need to re-check the side measurements. When these measurements are the same, your house is square. (See diagram below)
Setting out a building: Step 5.
Also use the below method to check if all corners are 90 degrees.
Using these methods to determine the starting out point and the corners of the house, you should be able to set out the house easily and accurately.