Locally based CSO Architects Inc. is working on plans to remodel a former Bally Total Fitness location behind the Fashion Mall at Keystone into its new headquarters. The 24,000-square-foot former fitness facility at 8831 Keystone Crossing is vacant and falling into disrepair, according to CSO's application for a tax abatement on the $1.8 million project. CSO bought the building and is working on plans for a sustainable renovation with LEED certification. If approved, the 10-year abatement would save the company about $56,000 in property taxes, roughly the same amount in additional taxes the company would pay for its planned improvements to the property. As part of the application, the firm pledged to create 10 new jobs and retain 70. The company's current headquarters is in the Parkwood Crossing office complex at Interstate 465 and Meridian Street. CSO, which was founded in 1961, previously occupied space at Keystone at the Crossing for about 25 years before moving to Parkwood Crossing in 1999, managing partner James Schellinger said. “Given these economic times and the cost of real estate, we thought we could find an existing building where the cost could be very advantageous right now,” he said. The firm expects to have the renovation completed by February, when its lease expires at Parkwood Crossing.