How do thermal breaks, insulation, and frame material selection influence condensation risk in curtain wall assemblies?

Condensation risk in curtain wall assemblies is controlled by the temperature of internal surfaces, vapour drive, and indoor humidity. Aluminium frames without thermal breaks conduct heat readily and create cold interior surface temperatures that can fall below dew point in conditioned spaces. Specifying continuous thermal breaks (e.g., polyamide strips or thermally broken frame systems) interrupts conductive paths and raises internal surface temperatures, decreasing the likelihood of condensation. Insulation in spandrel panels and behind frames adds resistance to heat flow and helps maintain uniform surface temperatures. Frame material selection influences both conduction and moisture behaviour: aluminium with thermal breaks provides a durable, lightweight solution; steel frames require careful thermal separation and corrosion protection; composite frames or those with integrated insulation may improve performance but must be validated for long-term stability. In addition to conductive thermal control, control of vapour ingress is essential: provide an internal vapour control layer or airtightness detailing at junctions to prevent warm humid indoor air reaching cold cavities. Glazing edge seals and warm-edge spacers with desiccant reduce internal IGU condensation risk. Hygrothermal modelling for the project’s climate and indoor conditions will identify condensation risk locations and guide specification of thermal break width, insulating materials, and sealing strategies. Also provide maintenance to preserve seals and gaskets; degraded seals can allow humid air ingress and raise condensation risk even with good initial detailing.