Profiles and Ground plates

Identify the location for the site of your project and setup a dumpy at a center point to obtain the site level.  By using building profiles and setup the better board then putting up the string line at the better board and make sure the string lines are Parallels and Diagonals .   There are example of how to set up the building profiles.


Building Profiles

1.	Peg the four outside corners: Determine the location of the building in relation to other buildings and boundaries , and place pegs in the ground marking the four corners of the building. Check to see if the pegs are square and form an exact rectangle. This can be done by making sure that: 1). Line AA-CC and line BB-DD are parallel. Line AA-BB and line CC-DD are parallel.(as shown in the drawing below) 2). The distance between peg AA and peg BB is the same as the distance between peg CC and peg DD. 3). The distance between peg AA and peg CC is the same as the distance between peg BB and peg DD. 4). The distance between peg AA and peg DD (the diagonals) is the same as the distance between peg BB and peg CC.
2.	The stakes should be at least 500mm out from the building line to allow room to dig the corner footing holes.  Make a level mark on all twelve stakes beginning approx 150mm above ground level, at the corner where the ground is the highest . Keeping the batter boards close to the ground saves the need for bracing. The height is only a reference height, so it does not really matter if the marks are slightly higher or lower, as long as they are all level.
3.	Fixing the batter boards to the stakes: Once a level line has been established and marked on all twelve stakes, proceed nailing batter boards to the stakes, so that the top of the batter board is flush with the level line marked on the stakes. The batter boards can be any sizes, and of boxing grade or low grade stock. Depending upon how far the profiles are set back from the building line.
4.	Put up the string line: Run a taut string line from batter board to batter board, passing directly over the pegs. Fix to each batter board between 2 nails, which will act as guide nails.
5.	Parallels and Diagonals: The following exercise is the same as in STEP 1. where the pegs on the ground were checked to ensure they were parallel and square. This time, the string line directly above the pegs needs to be checked so that it is also parallel and square. Check that the distance between the string line at point AA and BB and the distance between DD and CC are equal. If not, make any necessary adjustments by moving the string line in or out along the batter board and adjust the guide nails accordingly. The distance between AA and CC and the distance between BB and DD, also need to be equal. Make any necessary adjustments Once the perimeters are parallel, the diagonals need to be measured to ensure that the building line is square. Do this by measuring the distance between AA and DD and the distance between BB and CC (the diagonals). Make any necessary adjustments to ensure the diagonals are equal and if adjustments are required, re-check the parallels again, since altering the diagonals will also change the parallels. When the building lines are parallel and the diagonals are equal, the building line is then square. You now have a level, square building line to work from.