Building decay
Building decay refers to the deterioration of human-made structures over time, influenced by a variety of environmental and biological factors. As buildings are fixed in their locations and constructed from materials that age differently, they often become ill-suited to changing environmental conditions, particularly in the context of climate change. Rising global temperatures and shifts in climate patterns can lead to significant alterations in ecosystems, which may expose structures to new challenges. For instance, rising sea levels threaten many coastal buildings with inundation, while changes in rainfall patterns can overwhelm existing runoff systems, leading to flooding and foundational damage.
The processes contributing to building decay can be classified into biological, physical, and chemical agents. Increased humidity and temperature may facilitate the growth of invasive species and accelerate the biodegradation of materials, while physical decay can arise from increased sunlight exposure and mechanical stress due to altered wind patterns. Additionally, chemical decay is exacerbated by factors such as acidic precipitation and atmospheric pollutants, which can corrode and weaken construction materials. As climate change continues to evolve, the integrity and longevity of many structures are likely to face unprecedented challenges, necessitating a reevaluation of building practices and material choices. Understanding these dynamics is crucial for mitigating the impacts of building decay in the face of an increasingly variable climate.
Subject Terms
Building decay
Definition
Human-made structures have evolved architecturally for the environmental conditions in which they have traditionally been constructed. They are fixed in their locations and constructed from materials that age at different rates and with different consequences. As a result, most human structures are ill suited to almost any significant environmental change. Their long-term viability will likely be hampered by any change in climate or biological environment. Any change to the global climatic regime thus presents significant dangers to the integrity of most human structures.
Significance for Climate Change
If climate change continues to become more pronounced, rising temperatures and climate patterns will shift toward polar regions. As these shifts occur, ecosystems will also migrate, subjecting structures to new conditions. One likely and dramatic result of increased global warming is a rise in sea level. Even small changes in sea level would have spectacular localized effects, and, because a disproportionate share of the world’s population lives within 50 kilometers of a sea shoreline, a large number of human structures would be at risk of inundation, in which case the residents would become environmental refugees.
Changes in sea level would have dramatic effects on storm patterns, stressing many structures not designed to sustain severe weather conditions. Changes in rainfall patterns generally result in changes in runoff: Many foundations and gutter systems would prove inadequate for significantly increased runoff and would suffer from turbulent flow patterns. Extreme fluctuations in temperature, wind, and rainfall coinciding with global warming would result in changes to humidity, subjecting building materials to wetter conditions than they were originally designed to repel. Expected results would include accelerated material disintegration, mold infestation, corrosion, and rot, which would degrade and weaken structures and their foundations.
Low soil moisture conditions preceding severe rainfall events increases the impact and magnitude of flooding. In areas expected to undergo decreased soil moisture, floods will cause increasing amounts of damage. Between floods, the same low soil moisture could lead to increased ground movement, causing building foundations to degrade. Moreover, changing climate patterns often cause species migration. If this trend continues, buildings in areas previously unaffected by certain pests will need protection from an influx of destructive, invasive species.
Sea-level rise could cause changes to groundwater regimes, resulting in saltwater infiltration, subsidence, and drainage alterations, all potentially affecting the structural integrity of buildings. If shifts in global climatic conditions continue, buildings could be subjected to drastic changes in freeze-thaw cycles, oscillating between evaporation and and between wet and dry conditions. Changes in a range of conditions, including temperature, humidity, light, wind turbulence, and vibration, would all create stresses on buildings that they were not constructed to withstand.
As the effects of broaden, three basic agents of structural deterioration will be prominent: biological agents, physical agents, and chemical agents. These agents may contribute to decomposing a structure independently or by co-association. Increased humidity, higher temperatures, and sufficient water availability may allow for both the spread of and longer seasonal life cycles among invasive plants, insects, animals, algae, fungi, lichens, bacteria, and boring worms. If so, biodegradation of buildings would increase significantly. Higher populations of climbing plants, termites, ants, molds, roosting birds, and tunneling animals would negatively affect the mechanical and physical integrity of many structures.
Physical decay includes discoloration of building materials from radiation damage due to increased sunlight, such as may result from changes in cloud cover and from loss. Organic building materials, such as wood, straw, reeds, leaves, and grasses, suffer greater thermal decomposition when temperatures increase. Differential results in increased mechanical failures in porous building materials such as wood, stone, glass, and concrete. Mechanical stress due to increased sway and vibration from altered wind patterns also increases structural wear. Hygrometric stress due to changes in humidity can result in swelling and warping of organic and composite building materials.
Changes to weather patterns could subject many buildings to increased nonchemical erosion from windblown materials, such as dust and sand, and increase weathering due to water flow across their surfaces. Changes to global climate could result in changes to regional atmospheric chemistry, resulting in modifications to normal building-decay rates. Invasive windblown materials can increase static electrical charges, attracting dust, humidity, and soot to structural surfaces and enhancing chemical deterioration cycles.
As shifts in the climatic regime take place, chemical decay will likely increase in certain areas, as water and salts are introduced into porous structures, causing crystallization stress that may lead to mechanical failure. Stone and masonry buildings are particularly vulnerable to such stress. Organic materials may experience photodegradation by a combination of light, chemicals, and humidity, inducing destructive chemical changes. Humidity, chemicals, and temperature may also hydrate and make brittle structural materials such as glass, plastic, bronze, and copper.
Chemical dissolution and transformational stresses are also likely to increase in certain regions as global climate changes. Acidic precipitation—rain, snow, and fog carrying reactive solids, chemical pollutants, catalytic particles, trace gases, and corrosive compounds—is especially damaging to construction materials, including ferrous metals, granite, limestone, sandstone, marble, gypsum, dolomite, glass, and wood. Tarnished metals, rust, discoloration, exfoliation, acid etching, loss of surface details, decomposition, and enhanced weathering are all well-documented symptoms of atmosphere-induced chemical structural decay. Human behaviors release large quantities of reactive chemicals into the atmosphere as air pollution, resulting in increased acid deposition and enhanced structural decay. The chemicals responsible for these deteriorative effects are often the same chemicals implicated as causes of global warming and climatic change.
Bibliography
Brimblecombe, P., ed. The Effects of Air Pollution on the Built Environment. London: Imperial College Press, 2004.
Prykryl, R., and B. J. Smith, eds. Building Stone Decay: From Diagnosis to Conservation. London: Geological Society, 2007.
Samuels, R., and D. K. Prasad, eds. Global Warming and the Built Environment. London: E&FN Spon, 1994.
Smith, B. J., and P. A. Warke. Stone Decay: Its Causes and Controls. Shaftesbury, Dorset, England: Donhead, 2004.
Vandemeulebrouski, Isabeau, et al. "The Impact of Climate Change on Degradation in Historical Building Envelopes: Progress in Research Using Hygrothermal Models." Journal of Cultural Heritage, vol. 70, Nov-Dec 2024, pp. 334-363, doi.org/10.1016/j.culher.2024.10.005. Accessed 17 Dec. 2024.