How Do You Calculate The Mean Girth Of The Perimeter Of A Building?

1. Calculate total perimeter of external walls, using outer face.
2. Assuming all corners of building are right-angled, calculate the total number of internal corners subtracting the total number of external corners (rectangular building has 4 internal corners, 0 external corners), and multiply this by the average width of the wall (outside face of external wall to inside face of inner wall)
3. Deduct the above from the original perimeter to give Mean Girth (otherwise known as centre-line length calculation)

Measure the perimeter at points of interest, and calculate the mean by adding them and dividing by the number of measurements.

First of you should know all the sides of the proposed building, for a B3 house you add upall four of them then deduct or subtract the corners!