A heavy-duty 15x20 tarp is perfect for a D-I-Y project, protecting outdoor belongings, and more. These versatile, rot-proof, and waterproof tarps come in many colors as well. If you're looking for a durable protective covering for any reason, a 15 x 20 tarp is the way to go. A 15x20 tarp is a great all-around product to have. A 15 x 20 tarp will keep your equipment safe and protected. Many people use tarps to cover boats, ATV's and other motorized vehicles during the off-season.