by
Adam Bond, Architectural Preservationist
Vernacular Architecture
The homogenization of American architecture in the second half of the twentieth century was not the product of market forces in the simple sense. It was the product of a specific institutional and regulatory architecture — federal mortgage standards, zoning codes, highway construction policy, building material industry consolidation — that systematically suppressed local building knowledge and replaced it with nationally standardized products and methods. Understanding this history clarifies what is at stake in the preservation of vernacular architecture: not a sentimental attachment to old styles but the preservation of a body of practical knowledge about how to build well in a specific place.
Vernacular architecture, in the technical sense used by architectural historians and geographers, refers to building traditions that develop organically within specific geographic, climatic, and cultural contexts — as distinct from academic or high-style architecture, which is produced by trained architects working from formal design principles that may be applied anywhere. The distinction is less about aesthetic complexity than about the relationship of the building to its specific place: vernacular buildings are produced by people who know the local climate, the locally available materials, and the locally appropriate building practices in ways that general contractors working from national specifications do not.
The result of this local knowledge, accumulated over generations, is a building stock that is climatically calibrated in ways that nationally standardized construction is not. Pre-war building types common in Allentown — the double-wythe brick row house, the mixed-use commercial block, the masonry apartment building — reflect specific adaptations to the Lehigh Valley’s climate: the thermal mass of the masonry walls buffers interior temperatures against the diurnal swings that stress mechanical climate control systems; the proportions of windows and the orientation of building masses reflect centuries of accumulated practice about solar gain management in the temperate mid-Atlantic; the porches, the eave overhangs, and the ceiling heights of historic domestic buildings reflect an understanding of summer cooling without mechanical systems that no amount of post-war HVAC can substitute for.
The Lehigh Valley’s specific combination of hot summers, cold winters, significant heating and cooling degree days, and moderate but irregular precipitation created a specific set of building challenges that the vernacular traditions of the 19th and early 20th century addressed with specific solutions. The thick masonry walls that are structurally unnecessary by modern engineering standards serve a thermal mass function that dramatically reduces the amplitude of interior temperature swings relative to the exterior. The deep setback porches on residential buildings provided shaded outdoor living space in summer while allowing winter sun to reach south-facing windows. The operable double-hung windows at opposite ends of building plans enabled cross-ventilation during mild weather, eliminating the need for mechanical cooling during the shoulder seasons.
The suppression of this vernacular knowledge — through the modernist project of universal, climate-agnostic design that the manifesto describes — produced buildings that are simultaneously more energy-intensive and less livable under conditions of energy stress than the buildings they replaced. The hermetically sealed, mechanically conditioned building of the post-war era is a building designed for abundant, cheap energy. When energy is expensive, or when the grid is stressed, or when the air handling system fails, it becomes a building that cannot be inhabited without mechanical support. Historic buildings, by contrast, were designed to be habitable without mechanical support — they were designed to be inhabited by people in the climate they were actually in.
This is not a nostalgic observation. It is a prediction about future performance. The Climate Research Unit at the University of East Anglia, the IPCC Sixth Assessment Report (2021), and the US National Climate Assessment all project that the mid-Atlantic region will experience increased frequency and duration of extreme heat events, increased precipitation intensity, and continued shifts in heating and cooling degree day patterns over the coming decades. Buildings designed to manage heat through thermal mass and cross-ventilation — historic buildings — will perform better under these conditions than buildings designed to manage heat through mechanical systems alone, because they have passive strategies that do not depend on grid reliability or energy cost stability.
The argument for passive performance advantage in historic buildings has been supported by empirical building performance studies. Research by researchers at the College of Charleston and the University of Bath, among others, has documented that historic masonry buildings in similar climates consistently outperform modern construction on peak cooling load — the metric that matters most for grid stress — because the thermal mass of the masonry absorbs heat during the peak of the day and releases it during the cooler night, reducing the contribution of the building to peak demand periods. Lightweight modern construction, by contrast, heats and cools rapidly with exterior temperature fluctuations, producing higher peak cooling loads per unit area.
The specific character of Allentown’s vernacular — the brick bond patterns of specific neighborhood blocks, the cornice profiles of the late 19th-century commercial district, the row house proportions of the West End — is not available for purchase or specification. It cannot be reproduced by instructing a contractor to build something that looks like the existing neighborhood, because the appearance is the product of specific materials (local Pennsylvania brick of specific clay composition and firing characteristics), specific methods (cut and wire nails, lime mortar, riven lath), and specific craft knowledge (the proportion of window openings relative to wall area, the setback of the cornice from the wall face, the radius of the corner return on a Classical Revival trim profile) that are no longer widely held or widely practiced.
This irreproducibility has been documented empirically by urban geographers and preservation scholars including Max Page (University of Massachusetts) and Randall Mason (University of Pennsylvania), whose work on the cultural geography of American cities documents the systematic loss of place-specific architectural character through demolition, inappropriate infill, and material substitution. PlaceEconomics, the economic development consulting firm that has conducted the most rigorous quantitative research on the economic impacts of historic preservation in American cities, has documented across more than a dozen city-specific studies that neighborhoods retaining their historic fabric — their intact streetwalls, their fine-grained lot structure, their mix of uses — consistently outperform comparable neighborhoods that have lost their fabric on measures of economic vitality, business formation, and residential stability.
The PlaceEconomics research is particularly relevant to the Allentown context because it focuses specifically on mid-size post-industrial cities rather than major metropolitan markets. Their analyses of cities including Rochester, Utica, and Buffalo — comparable post-industrial contexts — found that historic districts in these cities provide higher Walk Scores than the citywide average, higher rates of small business formation, more diverse housing price points, and greater resilience to vacancy and disinvestment during economic downturns. These are not aesthetic outcomes. They are urban economic outcomes that happen to be produced by the same fine-grained, mixed-use, pedestrian-scaled fabric that the manifesto advocates preserving.
Page, Max. The Creative Destruction of Manhattan, 1900–1940. Chicago: University of Chicago Press, 1999.
Mason, Randall. The Once and Future New York: Historic Preservation and the Modern City. Minneapolis: University of Minnesota Press, 2009.
PlaceEconomics. Older, Smaller, Better: Measuring How the Character of Buildings and Blocks Influences Urban Vitality. Washington: National Trust for Historic Preservation, 2014.
PlaceEconomics. The Urban Vitality Blueprint: A Data-Driven Analysis of Equity, Affordability, and Vitality in San Diego’s Historic Districts. Washington: PlaceEconomics, 2025.
Intergovernmental Panel on Climate Change. Sixth Assessment Report: Climate Change 2021 — The Physical Science Basis. Geneva: IPCC, 2021.