Product Knowledge · 10 min read · Updated August 2026
Short version: 300gsm covers things, 500gsm works things, 650gsm survives things. The number on the quote is the single biggest driver of what your tarpaulin is actually capable of — and of how much you'll pay, not just once but over its whole life. Here's how the three weight classes actually behave, and how to pick yours without over- or under-buying.
| Property | 300gsm | 500gsm | 650gsm |
|---|---|---|---|
| Base cloth (typical) | 500D × 500D | 1000D × 1000D | 1000D × 1000D, denser weave |
| Hand feel | Light, flexible, foldable by one person | Medium, stiffens in cold | Heavy, needs two people |
| Tensile strength (typical) | ~1,200–1,500 N/5cm | ~2,000–2,500 N/5cm | ~2,500–3,000 N/5cm |
| Tear strength (typical) | ~150–250 N | ~300–450 N | ~450–800 N |
| Expected life, outdoor | 1–3 years | 3–5 years | 5–8 years |
| Relative price | 1.0× | ~1.5–1.8× | ~2.0–2.5× |
| Best for | Light covering, temporary, indoor use | General truck, construction, farm | Heavy haul, permanent, high wind |
Two things to hold onto from that table. First, the strength figures climb much faster than the numbers suggest — 650gsm isn't "twice" 300gsm in capability, it's in a different durability class entirely, because the base cloth and weave change along with the weight. Second, price climbs more slowly than lifespan, which is the whole reason under-buying is a false economy.
300gsm — light covering. Timber stacks under a temporary roof, machinery under a dust sheet, indoor partitions, short-term event coverage. It folds small, handles easily, and costs least. What it can't do is take sustained wind load on a truck, or survive years of UV. If the covering will be strapped and driven, or left out through summers, 300gsm is the wrong choice no matter the price.
500gsm — the general-work spec. The most common specification for a reason: it covers trucks, construction sites, farm equipment, and general industrial covering with acceptable life. It's the sane default when you don't have an extreme requirement. A 500gsm PVC tarpaulin will last several years in moderate UV, holds up to regular handling, and folds without needing a team.
650gsm — the heavy-duty spec. Where the covering is structural and failure is expensive: long-haul truck side curtains and flooring, permanent agricultural coverage, high-wind-exposure sites, anything strapped and loaded daily. It resists tear, holds welded seams under stress, and takes years of UV. The trade-off is weight and cost — and you shouldn't pay for it if you don't need it.
Rather than picking a weight and hoping, run the requirement backwards. Three inputs decide it:
Mechanical load. Is the tarpaulin strapped, weighted, or flapping in wind? A covering that sees daily wind flutter needs tear strength to survive the fatigue — 500gsm is the floor, 650gsm for constant high-wind exposure.
Exposure duration. How many summers of direct UV will it see? Two seasons of intense sun is a 500gsm job at minimum; five-plus is 650gsm territory, because UV costs thickness and coating integrity over time.
Consequence of failure. What happens if it tears? Dust getting on a machine is an inconvenience; a load of fodder or a finished product getting soaked can be a loss measured in thousands. Weight the decision toward the consequence.
Where all three point the same way, the choice is easy. Where they conflict — heavy load but short exposure, say — take the higher of the weight or the exposure requirement, because mechanical failure happens faster than UV degradation.
The over-buyer. A retailer buying tarpaulins to cover stock under a warehouse mezzanine — genuinely indoor, no UV, no wind, no load. He ordered 650gsm because "heavier must be better." He paid roughly double for strength the application will never test, and the extra weight made them harder to move and store. A 300gsm covering would have done the identical job for half the money. Over-buying isn't safer; it's just expensive.
The under-buyer. A trucking operator specified 300gsm to save on a fleet of flatbed covers, drawn by a price that looked excellent across 60 units. The first covers failed within a season — UV damage and seam fatigue from daily wind flutter at highway speed. The replacement cost, plus the downtime of re-covering trucks, exceeded the entire saving. The specification was right for the invoice and wrong for the road.
The right-sizer. A construction plant buyer specified 500gsm for general site covering and 650gsm only for the high-wind, year-round stockpile covers. Same supplier, same order — two weights matched to two requirements. He spent more than an all-300gsm order and less than an all-650gsm order, and got the lifespan he needed on each. This is what "choosing" a weight actually looks like: different weights in the same purchase.
Here's the trap that catches experienced buyers: "650gsm" is a weight, not a guarantee. Two tarpaulins both marked 650gsm can perform very differently depending on how the weight is made up.
Weight comes from two sources — the base cloth (measured in denier) and the PVC coating. A tarpaulin can hit 650gsm with a light base cloth and a heavy coating, or a heavy base cloth and a lighter coating. Those are not equivalent. The heavy-base-cloth version holds tear and tensile strength far better, because strength lives in the woven cloth, not the coating. The coating-heavy version can hit the gram target with less actual strength.
This is why a spec sheet should give you denier as well as GSM. If you only get GSM, ask for the base-cloth denier, or ask for the tested tensile and tear figures. And where you can, verify by weight: a genuine 650gsm roll of a known width and length has a predictable mass. If the roll weighs light, the grams aren't there.
Step 1 — Write down load, exposure, and consequence. Three lines. This is your requirement, and every other step serves it.
Step 2 — Set the floor from mechanical load. Dust and rain cover, indoor → 300gsm. Regular handling, road, or farm → 500gsm minimum. Daily wind load or structural use → 650gsm.
Step 3 — Raise the floor for exposure. Five or more years outdoors in strong UV pushes you up one class regardless of load.
Step 4 — Check the failure consequence. If a tear means a real loss, take the higher class. If it means inconvenience, you can sit at the floor.
Step 5 — Confirm the base cloth, not just the GSM. Ask for denier or tested strength figures. Verify delivered roll weight against the stated GSM, width, and length.
The most common ordering mistake isn't picking the wrong weight — it's picking one weight for a mixed requirement. If your purchase covers both light indoor covering and heavy road use, don't split the difference at 500gsm and get a product too heavy for one job and too light for the other. Order two weights. You'll spend less than an all-heavy order and get a correct product for each application. Weight is a specification, not a preference — and different applications deserve different specifications.
No. Heavier means stronger and longer-lasting, but if the application doesn't test that strength, you've paid for capability you won't use. A 650gsm cover for indoor dust protection is wasted money and extra handling weight. Match the weight to the job.
GSM is the total weight per square metre — base cloth plus coating. Denier measures the yarn used in the base cloth. Both matter: GSM tells you how much material there is, denier tells you how strong the structural part is. Two fabrics at the same GSM can have very different denier and therefore different strength.
Typically three to five years in moderate UV with regular handling, longer in mild climates and shorter under intense sun or constant wind flutter. Treat it as a range and lean to the conservative end for critical coverage.
You can approach it with a heavier base cloth and better weave at a lower total GSM, but you can't fully substitute — some applications genuinely need the material mass. If tear and tensile strength are your real requirement, specify those figures rather than assuming a GSM figure delivers them.
Weigh a roll of known width and length and calculate the grams per square metre. If it comes in materially below the stated figure, raise it with the supplier before accepting the delivery — and keep the measurement as evidence.
Yes, significantly. 300gsm folds small and moves easily; 650gsm needs two people and takes real space. If your covering is deployed and stored seasonally, the handling penalty of a heavier weight is a genuine cost, not just an inconvenience.
500gsm is the common general-purpose choice, moving to 650gsm for long-haul, high-speed, or constant-exposure applications where wind flutter fatigue and UV are both working against the fabric.
Pick the weight from the requirement, not from the price or a vague sense that heavier is safer. Set a floor from the mechanical load, raise it for exposure and consequence, and confirm the base cloth behind the gram figure. Then buy the weight each application actually needs — because the cheapest tarpaulin is the one you don't have to replace early.
