How should exterior plaster work be handled under adverse weather?

• A. Postpone when temperatures or humidity are unsuitable and implement weather-protective measures.
• B. Continue regardless of weather to meet deadlines.
• C. Only work during rain to keep surfaces cool.
• D. Replace plaster with another material when weather is unsuitable.

Answer: (A)

Exterior plaster needs stable curing conditions. If temperatures are too hot or cold, or humidity is too high or too low, plaster can’t cure properly. This can cause hairline cracks, reduced bond to the substrate, efflorescence, and a poor finished surface. The best approach is to postpone plaster work when weather isn’t suitable and, if it must proceed, use weather-protective measures to control the environment. That means shielding the work area from wind and rain, using tarps or enclosures, shading or cooling/heating to keep surface temperatures in a workable range, and managing moisture so the plaster can cure evenly. Replacing plaster with another material due to weather isn’t the standard fix; it’s about delaying or protecting to ensure a proper cure.