D.c.'s mayor. >> we encourage more property owners to follow their lead. >> reporter: mayor muriel bowser announcing planets for an abatement program incentivizing office-to-apartment building conversions and address the affordable housing crisis and revitalize the business district. still office-to-apartment conversions are no silver bullet. what are some of the challenges of converting an office building into an apartment space? >> it's endless. new plumbing, new electrical, new mechanical. so you're doing a lot of drilling. about a $65 million job. >> reporter: but cohen says the costs are ...