This Instructable is a continuation of http://www.instructables.com/id/Helter-Shelter/
using Coroplast instead of cardboard wardrobe boxes. Coroplast is a step up in durability since it is plastic and waterproof. Cost is reasonable at $17 per 4'x10' sheet from local retail. Coroplast folds easily like corrugated cardboard. I used a Dremel with a sheet rock cutting tool to slice one side of the Coroplast for easier folding. Standard Coroplast is not UV resistant, so painting or some other method of protection from the sun will be necessary if used outdoors for more than one season. UV resistant Coroplast costs more and is special order.