How to Design a Wood Bar Joist

Design the Wood Bar Joist

• 1

  Draw a rectangle that is 2 inches by 4 inches (often called a 2-by-4) horizontally across your grid paper. Label this A.

• 2

  Draw another 2-by-4 parallel to the first two squares above the first 2-by-4. Label this B.

• 3

  Draw a line going from the top of the left-hand side of A diagonally through two squares to the bottom of B. Label this C.

• 4

  Draw another line from the top of line C diagonally through two squares downwards towards the top of A. Label this D.

• 5

  Continue drawing diagonal lines like C and D until you reach the end of A and B.

Obtain Dimensions for the Wood Bar Joist

• 6

  Determine the length needed for your floor. This is the length of A and B.

• 7

  Determine the height the bar joist should be. They're usually between 6 inches and 1 foot.

• 8

  Multiply the height of the bar joist by itself. For example, 6 inches multiplied by 6 inches equals 36 inches.

• 9

  Determine the square root of the previous number. This is the length of C and D.

• 10

  Write the numbers you have determined in their appropriate places on the design.