Close Window
Click picture to enlarge
What you need:
  • 2 batterboards
  • 2' length of 1/2" rebar
  • String
  • Mallet
  • 4 wooden stakes
  • 2 green stakes or small wooden dowels
  • Tape measure
  • Knife
This method can be used to create a square or rectangular string line of any size. For this tutorial a 4' by 12' area is being marked off. Start by pounding a piece of rebar into the ground to mark one corner of the rectangle.
Click picture to enlarge
Measure away from the rebar 13' and pound in a batterboard. The horizontal section of the batterboard should be roughly 1-2" off the ground. Imagine a line extending from the rebar at a right angle to the first batterboard. Pound in the second batterboard along that imaginary line, 5' from the rebar.
Click picture to enlarge
Tie one end of the string to a batterboard. Don't tighten the string down too much around the batterboard because you will need to adjust it later. Pull the string taut, and loop it around the rebar a couple times. Move to the second batterboard, pull the string taut, and tie it off.
Click picture to enlarge
Following one leg of the string line, measure 3' away from the outside of the rebar. Use a green stake or a small dowel to mark the spot. Move to the other leg of the string line and measure 4' away from the outside of the rebar, again marking it with a small, round stake.
Click picture to enlarge
The Pythagorean theorem states that if one leg of a triangle is 3 units, one leg is 4 units, and the hypotenuse is 5 units, then the angle in between the legs is 90 degrees. Measure the distance in between the two marker stakes. The object is to get that value to be 5' by sliding the string along the batterboard. Adjust the position of the string on the batterboard until you have a 3' by 4' by 5' triangle.
Click picture to enlarge
Once you have the string line squared, you're ready to pound in two more of the stakes. Following the string line, measure 4' away from the outside edge of the rebar and pound in another piece of rebar. Do the same on the other leg of the string line, this time measuring 12'.
Click picture to enlarge
Hook your tape measure on the outside of the last piece of rebar you set. Pull it out, roughly parallel to the other 4' leg of the rectangle. Measure exactly 4' from the rebar, and use a knife to score a line in the dirt, perpendicular to the tape measure. Move to the opposite corner and measure exactly 12' away from the rebar, again marking a line perpendicular to the tape measure. The point where the two lines intersect should be the proper location of the fourth stake.
Click picture to enlarge
You can verify this mark by measuring the distance diagonally between the two corner stakes that are already in the ground. Hook your tape measure on the first piece of rebar and measure the distance between it and the marks you made in the dirt. If the values are identical, you have right angles all the way around your rectangle.
Click picture to enlarge
Pound in the fourth stake and run the string line the rest of the way around the rectangle. Tie off the ends and you're finished.