Maybe you just need to hang a tarp to cover or shelter a particular area, or as a floor or wall covering. In that case there's no problem, you just need to measure the length x width of the area to be covered. Often though, you need a tarp to cover a 3 dimensional object (a haystack for example). In that case measure the length and width of the top of the object you need to cover (you may need to estimate a little if it's not a flat topped object). Next you need to consider how far down the object, you want the tarp to drape over (in our haystack example you may only need the tarp to come part way down the object as in the image below).
If you need the tarp to cover for instance 1 metre on all sides then just add 2 metres to your length and width measurement so that the tarp will drape down 1 metre on all four sides. If you need to cover the entire object then measure from the top of the object to the ground, times that by 2 and add to the length and width measurements. Now you have it covered.Factor in the Cut Size: Another important thing to consider is that tarpaulins are provided in what's known as a'cut size. Cut size is an industry standard term which indicates the size of the tarp before it's seamed, hemmed and eyeleted. This means that the final size of any tarp can be as much as 30cms shorter than the size stated.
You need to factor this in when ordering your tarp. It's of course best to err on the side of caution, so if you think things might be tight it's best to order a slightly larger tarp size to avoid dealing with a shortfall. What Grade of Tarpaulin Do I Need? Tarpaulins are graded and measured by GSM (Grams per Square Metre). This is basically a measure of the weight and thickness of the material from which the tarp is constructed.
The higher the GSM number, the heavier, thicker and more robust the tarpaulin. All our tarpaulins are 80 GSM (Grams per Square Metre) waterproof, rot proof, UV protected with eyelets every metre and double edged, rope reinforced hems. This item is in the category "Home, Furniture & DIY\DIY Tools & Workshop Equipment\Hand Tools\Other Hand Tools". The seller is "toolsmartltd" and is located in this country: GB. This item can be shipped worldwide.