Three factors were considered when assessing the durability of the AeroBarrier
sealant – flexing, aging, and compatibility of the material.
• Flexing is an important characteristic, because most joints within the
building enclosure expand and contract due to changes in temperature
and/or moisture, which requires that the sealant material accommodate
• Aging is very important for the building industry because some materials
can break down over time due to leaching of plasticizers or other low-
molecular-weight volatiles, causing them to embrittle.
• Compatibility is important with all building products because the sealant
shouldn’t chemically react with or leach into other building materials.
• Flexing: The AeroBarrier material was aerosolized and deposited on
a 1/8-inch-wide wood joint. The joint was designed such that it would
contract by 20% at high temperature (180°F) and expand by 20% at low
temperature (-30°F). These temperatures were chosen as the worst-case
climatic extremes that could be experienced on a wall/roof assembly in North
America (high temperature includes the effect of solar heating). The joint
was cycled through this temperature range fifty times in an environmental
chamber to simulate the worst-case full range of joint movement over a fifty-
• Aging: The aging over that fifty-year period was simulated with an Arrhenius
relationship to accelerate any chemical degradation in the material with
temperature. During the fifty temperature cycles in the environmental
chamber, the duration at the high temperature (180°F) was extended for
each cycle to simulate the equivalent of fifty years of service life at the
sealant’s expected service temperature.
• Sealing Performance: The air permeance of the 1/8-inch-wide wood joint
was measured before and after the flexing and aging conditioning described
above (75 Pa pressure differential).
• Compatibility: The sealant was exposed to 41 different building materials
that were then conditioned in a warm, humid environment (120°F/95%
RH) for 10 days, followed by magnified inspection of the sealant-substrate interface.