By utilizing specially processed waste carpeting as a filler in the production of carpet backcoating, roofing materials, or other similar products, the amount of waste carpeting that is landfilled or otherwise disposed of is significantly reduced as is the need for mining the mineral fillers. Waste carpeting (post-consumer and/or waste from new carpet manufacture) containing calcium carbonate and a thermoplastic resin is collected and size-reduced to a size corresponding to the size of calcium carbonate typically used as a filler. The size-reduced waste carpeting is added as filler to at least one other material, such as polymers in standard latex, EVA, or PVC carpet backcoatings, to provide a composite used in the manufacture of a useful product (like carpet backcoating), and then the composite material is used to make the useful product (such as carpet backcoating, which is used as a primary or secondary backcoating in the manufacture of new carpeting). The waste carpeting may provide between 0-100% of the filler of carpet backcoating, with any remainder made up by conventional fillers, such as calcium carbonate.