We cleared a suitable area of ground in a disused chalk pit near the site of an old lime kiln.
We hope to use chalk from Whitlingham to make lime – which could be used to make building mortar.
To build a new lime kiln, we first need to make a flat, level, solid rectangular concrete area.
We need to use shuttering boards to form the concrete. The boards need to be fixed to stakes.
We drove 4 stakes into the ground to mark a rectangle measuring 1.5 by 2 metres.
One way to make a square corner is to use a folded ground-sheet or tarpaulin as a template – any folded flat surface makes a straight line and any folded straight line makes a right-angle!
We used another method …
To get right-angled corners we used a special set of numbers to make a triangle with sides 3, 4 and 5 units long. This was how square shapes may have been made in ancient times. A Greek named Pythagorus based a maths theorem on this idea.
We checked the shape was rectangular by making sure the diagonals were the same length.
The short sides were 1.5 metres, which is 3 times half a metre.
The long sides were 2 metres, which is 4 times half a metre.
So the diagonals needed to be 2.5 metre, which is 5 times half a metre.
We then drove each corner stake into the ground until the tops were all level.
Next week we will scrape the weeds and roots away and level the ground.
Then we will lay down “hard core” – sand and shingle to make a level base for the concrete
The shuttering boards we cut this week can then be nailed to the stakes.