In an age where baby boomers and millennial are returning to cities, density becomes a very important focus as developers and planners try to find ways to created new real estate where there is none. Allowable floor area ratio (FAR) in some of the densest urban areas in the country is on the rise, and in cities like Boston there is a race to the sky to develop as many units as possible on smaller and smaller parcels.
Many of the cities that are focusing on increased density are those that have historic downtown cores or neighborhoods. In both cases, there is sometimes a push to demolish older structures in order to create opportunities for greater density. In some cases, this is the most reasonable approach while in other cases the site may have more value by rehabbing the existing structure.
But which approach is best?
In historic neighborhoods, building scale is typically much smaller than downtown and FAR is usually capped due to zoning regulations on height. Existing open lots are rare and the only way to increase density on an existing site is to expand horizontally. In some cases this is attainable, but often it requires assembling multiple parcels, which can mean the demolition of non-essential structures and new construction that is out of scale with historic neighborhood. These projects often elicit a visceral response from community advocates.
A better option for attaining more density in an historic neighborhood may be an old factory building or large apartment building that was not required to comply with modern zoning codes or far exceeds allowable FAR. The reuse of this building would likely elicit a different response, especially if the use was compatible with the needs of the neighborhood, such as housing. Rehabilitating these kinds of buildings creates a sense of continuity that is often easier for a neighborhood to accept even if it presents the same issues as new construction, such as traffic or the need to provide services. In this case, density is hidden in plain sight.
Downtowns (or city centers) face issues relative to the decision to preserve historic buildings versus constructing new ones due to the fact most of these projects go vertical. Downtown districts tend to be marketable because of their historic character, and thus create demand for rehabilitated buildings. These are also the sections of a city that are best served by infrastructure, especially public transportation. The combination of historic character and easy access to trains and buses combined with the renewed interest in living in urban spaces has fueled the current wave of development. In this case height is not only about density, but the added value that comes with the view.
Midcentury office buildings, for example, are good candidates for reuse; particularly as housing. These buildings are too large to be economically feasible for demolition, but are no longer desirable as A-class office space. What they may lack in views, they more than make up for in architectural character and location.
In the recent urban growth for both city centers and surrounding neighborhoods, successful density is often achieved by leveraging old and new building stock. In these places, planners and developers have acknowledged that good preservation is part of good planning. Historic buildings not only provide a sense of place, but preserving them is often the most sustainable option and they are exempt from modern zoning codes that would otherwise limit any new construction. They are also ideal candidates for historic tax credits, making their rehabilitation more feasible financially.
With these factors in play, the value of historic preservation for the developer is undeniable.