Indoor Air Quality Issues During Construction

IEC performs onsite construction inspections to prevent indoor air quality (IAQ) and mold-related issues from arising during or after construction of new buildings. Regularly scheduled inspections during the various phases of building construction specifically target and identify conditions that affect indoor air quality. Observation reports are provided to the construction manager and architect, so that recommended remedial actions may be implemented before the condition is obscured or actually causes problems.

Water intrusion during construction is an inevitable aspect of new construction. Rain, humidity, dew, and other moisture sources can impact building materials in all phases of construction, from materials delivery and storage to open air construction prior to building enclosure. With any moisture intrusion comes the possibility of mold growth. Potential design or construction defects can also contribute to the potential for future mold growth in buildings.

Examples may include:

  • double vapor barriers,
  • poor roof drainage,
  • inadequate ground slope or foundation height,
  • obstructed weep holes,
  • inadequate sealing of roof penetrations and exterior walls,
  • drywall in contact with foundations, and
  • unsealed ductwork openings.


IEC conducts proactive baseline indoor air quality (IAQ) testing prior to occupancy which can insure that indoor air quality has not been impacted by construction activities. Pre-occupancy testing includes total volatile organic compounds (TVOCs), carbon monoxide, carbon dioxide, methane, formaldehyde, lead, pesticides, total fungal bioaerosols, large and small airborne particulates, radon, and ozone. Temperature and relative humidity measurements are also recorded to insure the appropriate functioning of the HVAC system. This testing is not only useful in verifying acceptable indoor air quality for the health and safety of the building occupants, but can establish a defensible position to assist in potential litigation against architects, builders, and owners. Potential indoor air quality issues that originate during construction may come from:

  • incorporation of formaldehyde-containing materials such as particle board and medium density fiberboard (MDF),
  • entrainment of construction dust and particulates into HVAC system components,
  • incorporation of high volatile organic compounds (VOC) content paints, varnishes, and thinners,
  • use of high VOC carpeting or adhesives,
  • uncapped sewer line clean-outs, and
  • dry P-traps and floor drains,

Pre-construction testing is performed before the start of renovation projects to provide a baseline for existing indoor air quality parameters. This assures that the construction manager is not held to a higher standard of indoor air quality than previously existed, and can provide assurance that the construction activities did not degrade indoor air quality of the renovated site or adjacent non-renovation areas. Post-occupancy testing during the first year of owner occupancy is useful in verifying the on-going performance of HVAC systems in controlling temperature, relative humidity, and particulate levels as well as verifying appropriate ventilation. Post-occupancy testing can also verify continued acceptable indoor air quality, as well as identify indoor air quality problems caused by maintenance and operations activities. Such testing in school buildings has identified high levels of carbon monoxide in a kitchen caused by incomplete combustion and inadequate ventilation of appliances, elevated methane levels caused by dry P-traps and breaks in sewer lines, high carbon dioxide levels in classrooms due to inadequate ventilation, and elevated particulate levels caused by inadequate filter media and infrequent change-out schedules.

Please call or e-mail IEC at for a template of our specifications for indoor air quality controls that may be incorporated into Section 01 5721 of construction specifications.

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