# How to Calculate Geotextile Quantities July 03 2014

## First, the easy way...

Table of cover with 1.2m overlap for 4.5m wide Geotextile:- This works out the number of strips that you need.
Multiply the number of strips by the length of each strip to calculate the amount required!
Simple!

## If you want to work it out the hard way... here's the algebra!

W = 3.3 n + P

### Let:

W = Width of Arena to be covered

L = Length of Arena to be covered

n = Number of strips of Geotextile required

P = Overlap specified

w = Width of Geotextile Roll

l = Length of Geotextile Roll

3.3 is derived from 4.5m (w) – 1.2m (P)

### Example (for a 40m Length x 20m Width arena):

20 = 3.3n + 1.2

and    3.3n = 20 – 1.2

n = (20 – 1.2) / 3.3 = 5.7 strips (use 6 no)

So:

l = (L + 0.5)6       (because we need length + 0.5m to dress up kicker)

l = (40 + 0.5)6     = 243m

or let 20m = L and 40m = W (laying the other way round)

n = (40-1.2)3.3    = 11.75 strips (use 12 no)

l = (20+0.5)12      = 246m

The rolls are 100m long so 3 rolls are required to complete the job.