Ballard Spahr is undertaking a two-year redesign and renovation project intended to give its Mellon Bank Center office space a more modern look.

Although the firm had considered moving from 1735 Market St., Chairman Mark S. Stewart said it was comfortable at the current location. He said the firm believes redoing the space is important to reflect the way work gets done today and will help attract and retain talent.

“We recognize people work and interact differently,” he said.

The changes will include a new office layout to give the space more natural light and areas for employee collaboration, as well as provide better views of the city. Demolition begins in November, and the work is scheduled to be completed by May 2014.