When creating a door or opening into the shelter, make sure to make it only large enough to allow a cat … The materials and tools to start making this outdoor cat shelter are: A Styrofoam cooler box. Choose stronger tape like duct tape or packaging tape. Making an outdoor cat shelter is a project that saves cats’ lives. Cut a piece of styrofoam … To prevent flooding, cut the opening so that the bottom of the doorway is a couple of inches above the ground. A tape. An eight-foot by two-foot sheet of hard Styrofoam, which is at least one inch thick; A yardstick; A box cutter; A generous supply of straw for insulating the inside of the shelter #2: Assembly. When John Medaglia built his home on a wooded street in rural Long Island, he didn’t realize the property was already inhabited. … Advantages: Styrofoam cooler is available from hardware stores, grocery stores, restaurants, etc. Simple to make.. Disadvantages: Lightweight – provides less protection from predators than a wooden structure.Cats may scratch Styrofoam. If you want to buy it you will only charge about $ 5. Create a shelter doorway. As with many of our low cost shelter options, this shelter … Using the utility knife, cut a small opening for the cat to enter and exit the shelter on the long side of the storage bin toward the corner.