Here's a link to a search of SCUP.org on this topic.

Authors Robert A. Brown and Paul Viccica in University Business magazine cover some of the permutations of the decision whether to build new or renovate and re-use. Nothing here is uniquely new to SCUPers, but it's a good collection of issues, and the authors suggest that "[r]enovating existing buildings might just be the new “new” for colleges and universities."

They consider the value of existing campus footprint in the campus core, the cost of building new over time and the costs of renovation and re-use, and the impact of the decision to renovate and re-use on potential town and gown frictions. 

Their bottom line:

Renovation and reuse are often thought of as “second-best” solutions, but they can be the optimum strategy and produce results every bit as effective as new construction. The more you look at renovation and reuse, the more appealing it is as an approach to planning, design, and building regardless of the economic climate.