A new technical brief from SPRI, the trade association representing the manufacturers of single-ply roofing systems and related component materials, addresses construction-generated moisture and its impact on commercial roofing systems.
Construction-generated moisture comes from activities including pouring concrete, burning propane heaters, painting, plastering, and drywall finishing. These activities can contribute to excessive levels of relative humidity inside the structure when proper remediation measures are not taken. Accumulation of condensation within the roofing assembly and within the structure can result when the temperature is at or below the dew point.
To control moisture, designers must identify the sources of moisture and develop a remediation plan during the design process. To reduce the probability of condensation, buildings under construction must be adequately ventilated, particularly during concrete hydration and other high moisture-related construction activities.
SPRI recommendations include avoiding the use of wet materials or materials with excessive moisture, installing vapor retarders in the roof assembly, avoiding penetrating vapor barriers, installing at least two layers of insulation, and always sealing deck-to-wall joints and gaps around roof penetrations.
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