Question

Determine the number of board feet required for joists on a one-story house 30′ × 40′, in which 2 × 8 joists will be placed 16″ OC.

A. 2,052
B. 1,224
C. 1,632
D. 1,536

I honestly don't know what formula to use for this. Everything I see online leads me to no answer on here.

Answer 1

Here is a hint: if you sketch out the floor plan you will see the entire area. Your joists will have to be all the way across the floor (to hold it up). And they are every 16 inches. If you break your floor up into 16 inch sections you will know how many joists are needed.

Answer 2

16" OC means a 2x8 every 16 inches.
40' = 31 joists
I'll assume the joists are 30' long
that's 930 ft of 2x8 =
a board foot is 12"x12"x1"

Answer 3

I'm still not understanding.

Answer 4

Is the answer B?