Almost every sizing question comes down to the same three steps: measure the area, add a margin for overlap and sag, then convert that into the width and length the net is actually sold in. Miss any one of the three and the numbers stop adding up.
Measure the surface the net has to cover in metres — length × width for a flat area, or length × height for a vertical run like a fence or scaffold. Do not estimate from memory: a greenhouse that "felt like ten by twenty" often turns out to be twelve by twenty-four, and the error compounds into a whole extra roll. Write down the longest and widest points, not the average.
Take your measured area and add three margins on top of it. Overlap: where two widths or panels meet, they must overlap by 15–20 cm, so add that for every seam. Sag and drape: a net that hangs over a tree or a structure needs extra length to gather and fix — add 10–15% to the linear dimensions. Fixing allowance: leave 20–30 cm at each edge to wrap around a post or peg. A good working rule is: measured area + 10–15% gets you close; then round up to the next whole roll.
Netting is sold by width and by the linear metre, not by the square metre. A shade net might come in 2 m, 3 m, 4 m or up to 12 m widths. So you do not buy "60 square metres" — you buy two 3 m widths at 10 m each, or one 4 m width at 15 m. Convert your area back into widths: divide the covered width by the roll width and round up, then multiply by the length. That is the number that goes on the order.
| Application | How to measure | Margin to add |
|---|---|---|
| Greenhouse shade | Roof length × width | +10% for tension and edge fixing |
| Bird net over trees | Canopy diameter + drop to trunk | +15% for drape and gathering |
| Hail net overhead | Row length × row spacing × rows | +15% for sag between supports |
| Windbreak fence | Fence length × height | +10% for tension and posts |
The four we see most often: measuring only the floor and forgetting the height a draped net needs; ignoring the overlap at seams so the joins pull open; buying by square metres and assuming the roll width will just fit; and not leaving tension allowance, so the net comes up short when it is pulled taut. Each is a cheap mistake at the measuring stage and an expensive one once the net is on order.
The fastest way to get it right is to send us the three measurements — area, width and the job — and let us do the conversion. Tell us what you are covering and we will return the exact widths, lengths and GSM, so the net fits the first time.
Measure the covered area in metres, add 10–15% for overlap, sag and fixing, then convert to roll widths by dividing the covered width by the roll width and rounding up. Order by width × length, not by square metres.
Add 10–15% on top of your measured area, plus 15–20 cm overlap at every seam and 20–30 cm at each edge for fixing. For draped netting over trees, go closer to 15%.
By width and linear metre. You buy a given width (e.g. 4 m) at a given length, so always convert your area back into widths and round up to the next whole roll.
Then the seams pull open or the edges come up short, leaving gaps the sun or birds find. Ordering the margin up front is always cheaper than patching a net that does not fit.
Measure the area, add 10–15% for overlap and sag, convert to roll widths and round up. Send us your measurements and we will do the conversion for you.