How to Choose the Right Tarp Intended Application Size and Dimensions Thickness and Weight Waterproof vs Water-resistant Assessing your needs will help narrow down the options and ensure the poly tarp you choose is suitable for the task at hand. Measure the area you need to cover and choose a tarp that offers adequate dimensions. It's better to go slightly larger than smaller to allow for ample coverage and secure fastening. One of the primary features of a poly tarp is to provide waterproofing and protection against moisture. Thicker tarps are durable and can withstand heavy rain, wind, and snow. For lightweight applications, a thinner tarp may suffice. Click below to download the comprehensive guide.