Indoor Playground is a custom made indoor softplay unit for children ages three to twelve.. The indoor playsystem measures 76 ft. wide by 21 ft. high and a length of 28 ft. The minimum room space required for this indoor playground is approximately 82 ft. room width with a 23 ft. ceiling and 34 ft. room length. Extra Large Size Indoor Playground. This playground is suitable to fit in a building or warehouse with a high ceiling.