Issue link: https://hi.iaq.net/i/248503
www.epa.gov/iaq/moisture • Insulation. Whether the general contractor is coordinating the installation of moisture control systems or a subcontractor is installing them, it is crucial to have a quality assurance program in place to inspect, test and document the correct installation and functioning of the moisture control elements. This may mean the difference between avoiding or having a moisture problem. Some examples of moisture problems resulting from poor or no quality assurance practices are: yy Insulation should be installed so that it makes as complete a layer as possible (i.e., no voids in cavity insulation, no uninsulated cavities). • Plumbing. yy The location of plumbing lines should be checked. yy Cold water lines, chilled water lines and internal roof drains should be insulated; pressure tests should have been completed prior to installation of insulation and enclosing finishes. • Missing flashing. • Flashing installed with laps reversed. • Flashing that stops short of becoming a through flashing. yy Access to valves should be available. yy Wet rooms should be assembled using only moisture- and mold-resistant materials. • Missing insulation. • Missing sealant. • HVAC. • Unsealed holes in the return plenum that cause depressurization of wall cavities. yy Condensate pans should be sloped and plumbed correctly. • Condensate pan drain lines, internal roof drains, or basement sump crocks installed at the highest point rather than the lowest. yy Access panels should be installed downstream of the coils so the coils and ductwork can be inspected and cleaned. • Impermeable flooring or moisture-sensitive flooring installed on a concrete slab that is releasing too much water vapor. yy Ductwork and return plenums should be air sealed and tested. yy Duct insulation should be installed and the ductwork sealed. Inspecting moisture control elements as they are installed is the most important aspect of supervision—especially in the areas where inspections may be most difficult. In addition to QA officers who are employees of the general contractor or subcontractor, inspections may be made by third parties such as construction management or commissioning firms. yy Chilled water and refrigerant lines should be insulated and sealed. • Wet materials. yy Materials that need to be installed wet or that became wet accidentally must be dry before cavities are enclosed (e.g., concrete, concrete masonry units or porous insulation must be dry before they are enclosed by gypsum board walls; crawlspaces must be drained and ground covering installed before OSB floor decking is installed) or flooring (e.g., vinyl flooring on concrete slabs) is installed on them. The inspector must check that the specified materials are on site and being installed so they will perform their function. Sequence is often important in effective installation. The following items must be frequently and carefully inspected during installation: • The air barrier. A number of tests may need to be performed to demonstrate that a moisture control element is working properly. Some of the tests are required by code; some may be specified by the designers in the construction documents; some may be required to maintain a manufacturer's warranty and some may be performed by the contractor for its own assurance. The tests include: yy Air barrier materials should be installed so they can be easily sealed at the joints and penetrations. yy Sealants that complete the air barrier should be installed before access to the air barrier is blocked. • Rainwater control. • Air tightness of the enclosure test (ASTM E779-10, ASTM E1827-96 [2002] or ACE [2012]). yy The shingling of the drain plane and the flashing for roof, walls, windows, doors and other penetrations should be correctly installed. 69