While not the lightest material for a groundsheet, Tyvek offers durability that can’t be matched by mylar, polycryo, or DCF. If saving money and maximizing longevity are important to you, then the ZPacks Tyvek Groundsheet is a great option. Large enough to cut to size tailored to your needs. Use the scraps to make a small (e.g., 24 inch square) porch mat for your vestibule or use it to keep your butt dry if you have to sit on wet ground.