Air Barriers: The Latest Tool in Moisture Control | |
There is more to controlling moisture intrusion in the building envelope than blocking liquid water. Vapor, as a result of air infiltration and diffusion can be significant as well. Recent studies put logical emphasis on the invisible culprit—air infiltration. Unseen source of moisture Under most circumstances, the dominant mechanism for water vapor transport is air leakage while vapor diffusion is relatively minor. The Energy & Environmental Building Association (EEBA) tested moisture movement through a 4x8 sheet of gypsum board and discovered that as much as 30 quarts of water is carried through the air leakage via a 1 in2 hole. Only 1/3 quart of water moves through the gypsum board via diffusion (movement of water vapor from an area of higher concentration to an area of lower concentration). | |
 | If allowed to pass freely through a building's envelope, moisture-laden air can cause condensation on wall system components, which can lead to moisture problems like mildew and mold. To combat the effects of moisture damage, designers are specifying the installation of air barriers in conjunction with water-resistant barriers and (where required by climate zone and other conditions) vapor barriers. The very specific functions and uses of each must be carefully considered. Water-resistive barriers, or moisture barriers, keep liquid water from entering the building enclosure. Vapor barriers, or vapor retarders, control the molecular diffusion of water vapor molecules through the actual material. They are not recommended in all climate zones. Air barriers create a near-airtight seal around all six sides of the home (floor, walls, and roof) to restrict the passage of air – and the moisture carried with it – through the building envelope. |
Icynene®, two-in-one insulation and air barrier creates an air-sealed building envelope and improves the thermal comfort, indoor air quality, and energy efficiency of the home. Icynene® is 100% water blown, HCFC-free, ½ pound spray foam insulation/air barrier material. It maintains its original R-value. Icynene® offers increased energy efficiency, advanced moisture management, and improved indoor air quality in one step.Icynene® gives builders greater control over air leakage so they can address what matters most to potential home buyers: 1. Energy efficiency Icynene® works as an insulation and air barrier to keep the home warm in the winter and cool in the summer. It also allows for rightsizing of the mechanical system and can also save homeowners up to 50% in heating and cooling costs. 2. Moisture management As a qualified air barrier, Icynene® helps reduce the movement of airborne moisture through the building envelope along with potential problems such as mold growth. 3. Indoor Air Quality (IAQ) 100% water-blown and environmentally-friendly, Icynene® helps create an indoor environment without drafts while it reduces airborne sounds and the intrusion of outdoor allergens, odors and pollutants. Combined with proper mechanical ventilation, occupants can control the quality of air they breathe. | |