It's a semi-enclosed balcony. In some ways, it's akin to Carnival's "cove balconies." However, unlike a cove balcony, which is generally an extension of a person's living room or dining room area, a privasea balcony is a separate space that can be used for relaxation or just enjoying the view. They're very popular in countries where property taxes include a portion that goes toward funding public services, such as police and fire departments. Because the balconies are private, they don't fall under this category so companies can build them out without paying additional taxes. The same thing can be said for any type of outdoor space that isn't being used as part of the main house. For example, a driveway that isn't being driven on or a patio that isn't being laid out with furniture - these areas aren't taxed. The size of the balcony will determine what kind of housing unit it creates. If it's small, perhaps 6 feet by 12 feet, for example, then you have a casita. A larger balcony might be used for a studio apartment or even a one-bedroom home. The actual number of square feet included within the boundary of the balcony determines how much tax revenue your city or county government receives.