Easily technique to setout building

 

            Setting out is the establishment of the marks and lines to define the position and level of the elements for the construction work so that works may proceed with reference to them. This process may be contrasted with the purpose of surveying which is to determine by measurement the position of existing features.

For setting out to be undertaken successfully good work practices should be employed since it is one application of surveying most of the techniques and equipment used in surveying are also used in setting out but in this discussion we are limiting ourselves to simple pegging using builder square method.

Firstly to determine the building lines: Assuming that the building line has been stated as a distance from the kerb of a road: Two square offset lines are set from the kerb to the position of the building line at a distance apart which is greater than the width of the proposed building. Pegs are positioned at these points, and a ranging line is fixed to these, giving the position of the building line.

Secondly to set out the base line: After taking the dimensions from the drawing, relating to its position, the frontage line should be set out. This will either be on the building line or behind it and he first corner peg (A) will be positioned from dimensions given on the drawing which relate to site features such as distance from a kerb, gate posts, boundary intersections etc.....

Thirdly to Set out the first right angle to the frontage line: Attach a taut line to the nail on a corner peg (B) and extend this well beyond the length of the wall to be set out then Adjust the line carefully to cross the frontage line at 90˚ by the use of a builder’s square and when the line is correct, knock in a peg (with nail) at a distance greater than the length of the wall, and attach the line tautly. Check for square again and adjust if necessary.

Fourthly to Set out the second right angle to the frontage line: Measure the same length of the building’s frontage line and set a peg (D) at same distance from the frontage line as peg C and Attach the ranging line and check the dimensions before continuing.

The fifth step is to set out the final (back) line: Measure the dimension for the length of the building’s side wall from the outer pegs on the frontage line and set pegs up approx. parallel with the wall lines,(Pegs E and F) then Attach ranging lines to the pegs to establish the back wall line which should be checked for parallel with the frontage line. The back corner positions, G and H, are at the intersection of the square lines. Pegs can be positioned at G and H, but this is not essential.

The next step is to check the building setting out for square ,When the building has been set out and proved by checking the diagonals, profiles can be erected to enable the corner points to be easily located after the trenches have been excavated.