By Earl Carr, Jr., President of Gulf 52, Hammond, Louisiana
Extreme heat puts stress on more than people and power grids. It also slowly damages the structures people live and work in every day. The long-term effects of sustained high temperatures on buildings often go unnoticed until the damage becomes serious. Understanding how heat affects different materials helps prevent costly repairs, safety hazards, and shortened building lifespans.
Heat exposure is not always sudden and dramatic like a fire. Long, hot summers, heatwaves, and constant exposure to high temperatures build up damage over time. Buildings in southern states like Louisiana, Texas, Mississippi, Alabama, Georgia, and Arkansas face these conditions year after year. Even well-built structures are vulnerable if extreme heat is not factored into design, maintenance, and inspection practices.
Concrete is one of the first materials impacted by prolonged heat. Concrete naturally expands in the heat, and repeated cycles of expansion and contraction create internal stress. Over time, microcracks form inside the material. These cracks allow moisture to penetrate deeper into the concrete. When temperatures drop and moisture freezes or evaporates, internal pressures increase, causing surface spalling and deep structural degradation. The concrete may look solid on the surface, but inside, it loses strength and durability.
Steel reacts differently but is no less affected. Steel expands when heated, and if it cannot expand freely due to surrounding materials, stress builds up at connection points. Over many years of exposure, steel can permanently warp or bend. Heat also weakens steel’s molecular structure, lowering its yield strength. Beams, columns, and trusses exposed to extreme temperatures may no longer support loads as intended. Small shifts can lead to larger problems like sagging, cracking around supports, or, in worst cases, catastrophic structural failures.
Wood, another common building material, changes significantly under prolonged heat. High temperatures dry out wood fibers, leading to shrinkage, warping, and splitting. The loss of internal moisture makes wood more brittle and less able to absorb stress. In addition, extreme heat can cause chemical changes in wood, weakening the bonds that give it flexibility and strength. Once wood is weakened, it becomes more susceptible to pests, rot, and structural failure even if the initial damage is not obvious.
Masonry materials like brick and stone generally hold up well under normal temperature ranges, but extreme heat still creates hidden problems. Mortar joints between bricks and stones expand and contract during high heat cycles. These movements eventually weaken the bond holding the masonry together. Cracks start small but grow over time, allowing water to enter and accelerate the damage through freeze-thaw cycles or erosion. A wall that looks sound today might show significant structural gaps a few years down the road.
Roofing systems are particularly vulnerable to extreme heat. Asphalt shingles can soften and deform when exposed to sustained high temperatures. Shingles may curl, crack, or lose their protective granule coating, leaving roofing felt and structures exposed to moisture damage. Flat roof membranes can blister, shrink, and pull away from seams. Metal roofing expands significantly in the heat, putting stress on fasteners and joints, which leads to leaks and misalignment.
Insulation performance also declines under repeated high-temperature exposure. Foam insulations can break down, losing their thermal resistance and releasing volatile organic compounds into indoor air. Fiberglass insulation can compress and settle, reducing its effectiveness and creating temperature imbalances inside the building envelope. Poor insulation performance leads to higher energy costs and greater wear on HVAC systems.
Mechanical and electrical systems inside structures are not immune to the effects of extreme heat either. Prolonged exposure dries out wire insulation, increasing the risk of electrical shorts and fires. Mechanical seals, gaskets, and plastic components degrade faster in hot conditions, shortening the lifespan of critical systems like air conditioning, water heaters, and pumps.
Preventing or minimizing the long-term impact of heat exposure starts with awareness and routine inspections. Regular monitoring for cracks, shifts, surface deterioration, and equipment wear is critical. Inspections after long heatwaves or unusually hot seasons should focus on structural joints, roofing surfaces, concrete slabs, and visible support systems.
Using the right materials during construction and renovation also makes a difference. Materials designed to withstand higher temperatures perform better over time. High-performance concrete mixes, fire-retardant treated lumber, metal alloys with better heat tolerance, and reflective or ventilated roofing systems help reduce heat stress on the building envelope.
Designing for better airflow and shading reduces the amount of direct solar load on structures. Features like awnings, ventilated attic spaces, thermal breaks, and light-colored exterior finishes help buildings manage heat buildup more effectively.
When heat-related damage is discovered, early action saves money and reduces risk. Repairing small cracks, reinforcing connections, replacing damaged roofing, and updating compromised insulation are manageable if caught early. Waiting until structural damage becomes obvious usually means larger repairs, higher costs, and longer disruptions.
Extreme heat is not just a seasonal inconvenience. It is a real structural risk that compounds over time. Southern buildings, especially, face repeated exposure year after year. Factoring in heat’s long-term effects during construction, maintenance, and restoration protects property investments and ensures structures remain safe, stable, and efficient for decades to come.
Understanding how heat affects every part of a building is key to building smarter and managing risk more effectively over time.
