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Cut Height – Using a laser level and RL

Cut Height

Determining cut heights and Finished Floor Levels is not hard, but having it explained in a simple way is very useful. Here are the steps…

…but before we start, there are a few assumptions to note, these are:

  • you have a self levelling laser level (red or green beam)
  • You have an RL (a line on a stick somewhere that indicates the natural ground level height for example 28,000)
  • You have a cut level from the plans

The steps to determine how far to cut are:

  • Set up your level and turn it on; make sure that the laser is located above the final cut line
  • Place a stick on top of the block where the RL is located
  • Grab your laser receiver, find the laser level and lock the receiver to the stick
  •  Mark that spot as “RL height” for example 28,000
  • Now wherever you walk around with the stick, the bottom of it will be at 28,000 when the receiver is inline with the laser level
  • Finally, to work out where your cut level is, you have to follow the steps in either one of the two scenarios below.

Scenario 1: your cut height for a section of the land is higher than your RL (e.g. 29,240 for a patio slab)

    1. The difference is 28,000 – 29,240 = -1,240
    2. that means that the cut level is 1,240mm above the RL
    3. now measure 1,240mm below the RL line on your stick and write “Top Cut” or “Cut Level”
    4. at that measurement, set your receiver
    5. now you can walk around and whenever the receiver is in line with the laser level, the bottom of your stick is at the cut level

Scenario 2: your cut height for a section of the land is lower than your RL (e.g. 26,350 for a carport slab)

    1. The difference is 28,000 – 26,350 = 1,650
    2. that means that the cut level is 1,650mm below the RL
    3. now measure 1,240mm above the RL line on your stick and write “Cut Level” 
    4. at that measurement, set your receiver
    5. now you can walk around and whenever the receiver is in line with the laser level, the bottom of your stick is at the cut level

 

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