Using the 'rule of thumb' method for calculating the depth of a floor joist, the depth of a joist spanning 3.6m would be
A) 150mm
B) 175mm
C) 200mm
D) 225mm
E) 250mm

Question

Quizplus · Accepted Answer

The 'rule of thumb' for calculating the depth of a floor joist is to divide the span (in meters) by 20. For a span of 3.6m, 3.6/20 = 0.18m or 180mm. The closest standard depth greater than this calculation is 200mm.

Using the 'Rule of Thumb' Method for Calculating the Depth