There are many reasons to build an Accessory Dwelling Unit or ADU (commonly called a casita around Tucson): extra space for a guest, a home office, an art or writing studio, or even for additional income through rentals. However the most frequent driver, by a landslide, is for intergenerational housing.  A majority of the casita projects we’ve built in Tucson to date have been for intergenerational housing: a place for grandma, a nephew, or a developmentally disabled brother.