The most resistant material to mother nature is found at semi truck tarp centers. That stuff holds up to anything, waterproof, strong, hard to rip or tear. Over the past 25 yrs, I have had three covers made, not one has ever failed !! Even standing water and snow has never affected them, and traveling down the highway at 70 mph flapping in the wind has not destroyed them. Yes you will need to add vents, easy to do, and yes they are heavy, probably can't handle by one person....but it will be the last you ever buy !! They also have different material weights for light duty up to heavy duty.....