Wayfair Inc., one of the world’s largest online retailers for home furnishings and decor, is expanding into a nearly 900,000-square-foot facility near Cincinnati/Northern Kentucky International Airport.  A joint venture between Dermody Properties, a national industrial development and operating company, and Hillwood Investment Properties will develop an 898,560-square-foot facility for Wayfair.   Paul Hemmer Co. is the general contractor for the project. ATA Beilharz Architects is the architect.