Thermal shock refers to the structural stress and damage caused when roofing materials (like metal panels or flashing) expand and contract rapidly due to sudden, drastic fluctuations in temperature. This occurs when a roof surface heats up intensely during the day and is suddenly cooled by a rainstorm or a sharp drop in temperature at night.
Roofs made of metal or single-ply membranes (like TPO or EPDM) are particularly susceptible, as the materials stretch in heat and snap back in cold. Over time, this cycle can cause seams to split, fasteners to back out, or the material itself to crack.
In Central Texas, roof surface temperatures can easily reach 160°F in the summer and drop rapidly during afternoon thunderstorms. To mitigate this, high-quality flexible membranes or metal roofs with “floating” clips (which allow for movement) are often used to prevent structural failure.