A polyethylene tarp is not a traditional fabric, but rather, a laminate of woven and sheet material. The center is loosely woven from strips of polyethylene plastic, with sheets of the same material bonded to the surface. This creates a fabric-like material that resists stretching well in all directions and is waterproof. Sheets can be either of Low density polyethylene (LDPE) or High density polyethylene (HDPE). When treated against ultraviolet light, these tarpaulins can last for years exposed to the elements, but non-UV treated material will quickly become brittle and lose strength and water resistance if exposed to sunlight.
Canvas tarps are not 100% waterproof, though they are water resistant. Thus, while a little bit of water for a short period of time will not affect them, when there is standing water on canvas tarps, or when water cannot quickly drain away from canvas tarps, the standing water will drip through this type of tarp.
Vinyl tarps are industrial-grade and intended for heavy-duty use. They are constructed of 10 oz. per sq. yd. (approximately 340 g/m2) -weight coated yellow vinyl. This makes the tarp waterproof and have high abrasion resistance and tear strength. These resist oil, acid, grease and mildew. The vinyl tarp is ideal for agriculture, construction, industrial and trucks.