What does it take to convert office space to housing?

A new report by SPUR, the San Francisco Planning & Urban Research organization, provides some great ideas for what it takes to convert downtown office space into housing.  The report differs from some previous studies because--importantly--it takes into account developer viability of the projects.  The take-away is that it won't be easy to do this in many markets, but it's important work:  SPUR notes that San Francisco's downtown office vacancy rate is 28% and there are up to 11,000 units that are commercially viable.  BUT...it will take a lot of policy re-invention, including:  changes to the planning and building codes; changes to impact fees; and maybe even some developer incentives and tax breaks (think TIF and property tax breaks for affordable units) to make developers begin to do this type of development at scale.