Even while the likelihood of tax reform in 2015 is questionable, historic preservationists are actively lobbying to save the historic preservation tax credit from the chopping block. Currently, developers who renovate historic buildings can receive up to a 20% tax credit, significantly reducing the cost of renovation relative to redevelopment. New York Preservation League President Jay DiLorenzo is leading the effort to increase the historic preservation tax credit to 30% rather than eliminating the break. Those in support of the tax preference argue that preservation makes neighborhoods more affordable, more walkable, and even more conducive to innovation than neighborhoods in which market incentives guide re-use versus redevelopment incentives.
Findings from the three study cities show that mixing buildings from different vintages—including modern buildings—supports social and cultural activity in commercial and mixed-use zones. Many of the most thriving blocks in the study cities scored high on the diversity of building-age measure. Scale also played an important role. Grid squares with smaller lots and more human-scaled buildings generally scored higher on the performance measures than squares characterized by larger lots and structures. These results support the concept of adding new infill projects of compatible size alongside older buildings.
Preservationists frequently point out that Jane Jacobs favored preserving old buildings with her famous quote:
Cities need old buildings so badly it is probably impossible for vigorous streets and districts to grow without them…. for really new ideas of any kind—no matter how ultimately profitable or otherwise successful some of them might prove to be—there is no leeway for such chancy trial, error and experimentation in the high-overhead economy of new construction. Old ideas can sometimes use new buildings. New ideas must use old buildings.
She favored preservation for both the cheap rent that older and perhaps run down buildings could provide for new businesses and for the aesthetic qualities and level of density that walk-up buildings in traditional neighborhoods provide. She correctly identifies that a variety of rental rates within neighborhoods and blocks allows for diversity and vibrancy that isn’t possible when rental rates are constant across the buildings in a neighborhood. Preservationists and perhaps Jacobs herself attribute this correlation is to entrepreneurs finding inspiration in old buildings rather than new businesses locating in their cities’ least expensive buildings.
However, both Jacobs and preservationists today fail to acknowledge that the cities and neighborhoods where preservation is strongest have uniformly high rents and low diversity because preservation efforts have led to insufficient building supply. Jacobs contrasted preservation with government-led urban renewal efforts relying on eminent domain to raze and reconstruct entire blocks and neighborhoods. She correctly points out that the resulting new construction would be more expensive than protecting old buildings from eminent domain. But this is a false dichotomy. Market-led redevelopment is very unlikely to result in uniform new construction. More likely, developers will gradually redevelop or renovate parcels as it makes sense to do so, creating blocks and neighborhoods with buildings of varying ages that are affordable to diverse residents and businesses of various types.
Ed Glaeser finds that in New York City, per-square-foot real estate prices have risen an order of magnitude more rapidly than prices outside of these districts from the 1980s to the 2000s. Neighborhoods like New York’s Greenwich Village and Boston’s North End are undeniably charming, but today they’re home to universally expensive housing and retail, hardly the bastions of diversity that Jacobs espoused.
Undoubtedly, local level preservation rules that create historic designations are more distortive than the historic preservation tax credit which marginally encourages developers to renovate rather than redevelop. But incentivizing historic preservation over new construction makes cities more expensive by reducing supply. Some types of “creative class” businesses might truly prefer to locate in older buildings with character, but old buildings only support diversity of land use to the extent that they provide cheaper space than new construction. Slum clearance is no longer driving high real-estate costs in the most expensive neighborhoods. Historic preservation is now the culprit, ensuring that old buildings go to those wealthy enough to afford them rather than providing inexpensive space for new businesses.