Facts About Moisture and Fiberglass Metal Building Insulation
nlike many other insulation products, fiber glass metal building insulation is often visible to the occupants of the building. Making sure that roofs and walls do not leak, that the product is clean and dry prior to installation, and that condensation is controlled after installation is critical to the insulation performance and to the building’s interior aesthetics. Because of performance requirements, fiber glass metal building insulations are most frequently installed with a facing material laminated to the surfaces that may be visible.This facing serves several purposes:
Provides vapor retarder protection to retard passage of water vapor through the insulation to cold surfaces where condensation can occur
Protects the insulation from damage
Provides light reflectivity
Provides an aesthetic appearance Fiber glass metal building insulation will provide long service life and optimum performance when a few simple precautions are followed.
The insulation should be kept clean and dry prior to installation and applied only to clean and dry surfaces. Care should be taken to protect the insulation from the incursion of water during the installation process. If adequately designed, regular inspection and maintenance of the vapor retarder will protect the integrity of the system after installation.
What effect does moisture have on insulation performance?
Moisture from rain, ground water, humidity or other forms of condensation creates the potential for several problems in metal buildings. First, the presence of water (or ice) in the insulation seriously degrades the thermal performance and can degrade the effective service life of the insulation system. Second, water in contact with metals can contribute to corrosion and degrade the service life of the building.Third, collection of water can lead to dripping, staining, and other undesirable effects such as mold, mildew and odors, which degrade the building’s intended service.
Should wet insulation be replaced?
Yes. When fiber glass metal building insulation is exposed to storm waters or flood damage, the wet insulation should be removed and replaced since the water may carry with it any number of unknown contaminants. Although it is possible for the thermal and acoustical performance of fiber glass insulation to return if the material is allowed to completely dry out, there is no assurance that the drying method used will be effective. There is also no assurance that the forces acting on the wet insulation will not result in loss of thickness, or that contaminants in the water will not contribute to corrosion, mold or mildew growth or odors. For these reasons, it is best to err on the side of caution and replace the insulation. Fiber glass metal building insulations must pass the mold growth test as specified in ASTM C991: Specification for Flexible Glass Insulation in Pre-Engineered Buildings. Clean, dry fiber glass will not support mold or fungus.1 However, once the insulation – or any product, for that matter – is exposed to dirt and moisture, the possibility for microbial growth (mold or mildew) exists.2 Replacing the wet insulation is recommended to reduce the potential for indoor environmental quality problems and to regain the energyefficiency and acoustical requirements intended for the building.
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