Durable Footer Form. Cardboard forms work fine as long as it doesn't rain before the concrete arrives. Bigfoot Tube 8 is a 4-foot-long 8-inch-diameter tapered cone made from recycled high-density polyethylene. It consists of four nestable sections that collapse into a 12-inch-tall package for easy transport or storage. A plastic top keeps out dirt and moisture. The tube is compatible with all Bigfoot concrete footers and costs about $10. Bigfoot Systems, 800/934-0393, bigfootsystems.com.