A catio, accessed through the open window, lets cats enjoy fresh air, sunshine, and bird-watching without the chance of getting into trouble. Senior technical editor Mark Powers built this two-story version, complete with a shelf for perching, over two days using rot-resistant cedar, in a look and color that match the home’s architecture. Get all the steps. #catio #DIYcatio #petproject #petfriendlyproject #howto #freecatioplans #freeplans #homeimprovement