Adding a carport could increase your home’s resale value if undervalued in your neighborhood. Consider building a garage instead if you’re interested in increasing your home’s resale value. Building a garage costs about $30,000 and has an estimated return on investment (ROI) of 80%.  “Some municipalities require adding a carport in order to allow converting the existing garage into inhabitable space or a living unit, but on its own, the increased value of a carport would not be significantly more than the cost of the carport itself,” says Ezra Laniado, Expert Review Board member and owner of Landmark Construction & Development Group Inc. in Los Angeles.