Filled standard polypropylene sandbags are the most economical filled sandbags available on the market. Polypropylene sandbags are the most commonly used type of sandbag in the industry. The most common use of polypropylene sandbags is for flood prevention and ballast weight for construction activities. Woven polypropylene sandbags resist punctures and tears with a strong 10x10 weave / 900 denier and UVI protection - lasts 1,600 hours in the sun. Dense, tight weave holds almost any dry substance.