Study the working drawings and centre line drawings before starting the actual line-out.
Check all the measurements and distances and tally them with each other.
Locations and orientations of the columns should be such that all internal dimensions of the rooms, passages, ducts etc, match the working drawing without any obstruction.
If any discrepancies are observed, get them rectified right away from the Architect.
Clear the central portion of the plot, remove the unwanted grass, bushes etc. and level the plot.
Take required side margin and set up the theodolite.
Mark a parallel line from all the four sides of the building line @ 1.5 meter (5’0”) away and erect a brick pillar or mundhas (wooden post) on this line.
Mundhas (wooden post) should be erected by making pits about 60 cm deep and pour concrete in these pits for firm fixity.
The centre-to-centre distance between mundhas (wooden post) should not be more than 2.5 m.
Construct brick pillars, if any, in the centre of each column.
For brick pillars, railing planks are not required. But, in case of mundhas, fix these planks at a distance of about 1.0 meter above G.L.
This railing should be of good quality wooden planks, of size 15 cm x 4 cm (6” x 1.5”). Avoid using bent/cracked planks. The railing should be nailed to mundhas (wooden post) in level, using 50 mm long wire nails.
Set up the theodolite on one corner of the building (marked earlier on pillar) and bisect the building corner marked on the other side of the pillar.
Move the telescope vertically, bisect the railing plank and fix nails on both the railings. This will be the face line of the building, i.e. 0.0 marking.
Similarly, set up other face of the building, which will be 0.0 marking nail for other face.
Repeat the procedure to fix two faces of the building.
Mark nails on all four corners of the building. Check diagonals using two tapes at a time. Both the diagonal distance should be the same as
Where C = diagonal
A = one side of the building
B = other perpendicular side of the building.
If any difference is observed in the diagonals, slight shifting of the proper nail on the railing is needed. After every shifting of any nail, check all the dimensions and setbacks. Repeat the procedure to obtain correct sizes and diagonals.
After the correct layout of four corners of the building and exact diagonals are obtained, start centre marking for every column.
By using steel tape, measure the distance of each column and fix nails for each centre of the columns on one side.
Repeat the procedure on all four sides and fix proper nails.
For markings, use white oil paint on railing and write all column numbers by red oil paint, for ready identification near respective nails.
Inform the Architect and get the centre line marking checked. The Architect should check all the nailing measurements and numbering of the same. He should be also check the setbacks for the buildings, before giving N.O.C. for the work. This is a final N.O.C. for line-out.
After final N.O.C. from the Architect is obtained, start lineout marking for column pits to be excavated, on the ground.
A nylon string should be fixed to the nails for particular column numbers on both the axis. Crossing point of both the strings will be the centre of the column.
Put the plumb bob at centre of the column; mark by lime powder as [+] and then side of excavation for footing should marked on ground by lime powder.
Repeat the procedure to locate the centre of column.