PROFILES AND DATUM POINTS

SETTING OUT PROFILES



This process takes a bit of checking and changing and double checking which is essential cause the profiles gives us our FFL (final floor level) our Jack Stud Heights which every vertical measurement are measured too at our datum point (1.), and our BL which every horizontal measurement is measured from at our profile/batter boards, 330 mils this way 30 mils that way etc,


· STEP 1


1. So firstly we started working out the minimum lengths for our batter / profile boards and leave sufficient room for our building line and also the lines for our Jack stud / Bearer lines (which were 30mm,330mm and 630mm in from our building lines) and joist lines(which were 300mm and 600mm in from our building lines).


2. Once we worked out the lengths of our batter boards / batter board plates we were able to start setting out our profiles, these were to be 1m out from our building lines.


3. Once we marked it out we were than able to start putting in our profile plates and uprights and bracing them, we had to brace each upright with at least two braces as to keep it square, with braces going perpendicular to each other.

· STEP 2


Once we set out our uprights we than had to find our datum point (1.), this point is the point to which all vertical measurements are measured from. To find our datum we had to use a dumpy and staff (2.); we went around and measured the height at the corners of each profile. The lowest measurement was our highest ground level point and therefore our datum point.

· STEP 3


1. Now that we had our datum point we were able to get our FFL which was 850mm (3.) high at the datum point, we started by putting up the profile boards at the datum point first and leveling them out.


2. Then we went back to our dumpy and got the measurement up from our datum point profiles and marked this on our staff, we were than able to find the height of the other profile boards by using the dumpy and staff, by moving the staff up or down until the line on the staff lined up with the middle line in the dumpy and made a mark at the bottom of the staff onto the corner profile uprights, this then transferred a level horizontal line from the datum point to the three other profiles.


3. We then put up the rest of the profile boards only partially nailing them in, once they were all up we were than went back over and double check the height and fasten them properly once the heights were right.

· STEP 4


1. Now that we had our FFL we were able to get our jack stud height profile boards which was 400mm below our FFL, we done this by using the same process to get our FFL profile boards up.

NOTE 1: A datum point is the point to which all measurements through the dumpy are taken, this point is always the highest point on the site. You need be particular with all your measurements at this point, as if you get it wrong here you than transfer it to the other points wrong.

NOTE 2: A dumpy and staff is used in a system for transferring a height from one point to another at a level horizontal line

NOTE 3:To get our FFL we added our bearer (190mm), Joist (190mm), particle board (20mm), jack stud plate(50mm), and jack stud(400) which gave us a FFL of 850mm and a jack stud level of 450mm at our datum point.