Marking, Setting Out Of Foundation

Marking, Setting Out Of Foundation

Setting out is the process of laying down the excavation lines and centre lines on the ground before excavation is started after the foundation design is done

For setting out the foundation of a small building the centre line of the longest outer wall of the building is first marked on the ground by stretching a string between wooden or mild steel pegs driven at the ends

Two pegs one on either from the central peg are driven at the each end of the line

Each peg is equidistant from the central peg and the distance between the outer pegs corresponds to the width of foundation trench to be excavated. Each peg may be projected  about 25 to 50 mm above ground level may be driven at a distance of 2m from the edge of excavation

When the string is stretched joining the corresponding pegs at the two extremities of the line the boundary of the trench to be excavated can be marked on the ground with dry lime powders

A right angle can be set out b forming 3, 4 and 5 units long

The centre line of the other wall which is perpendicular to the long wall can be marked by setting out right angles

All the specifications are made by tape or prismatic compass may be used for setting out right angles

Similarly outer lines of the foundation trench of each cross wall can be set out

For big project reference pillars of masonry is constructed first, these pillars may be about 20cm thick and 15cm wider than the width of the foundation