How to Control Moisture with Air Sealing in Northeast Homes
Moisture problems start with air leakage. In many homes, that means up to 30 quarts of water moving into the walls each week.
Testing by the Energy and Environmental Building Association (EEBA) shows that a 4×8 sheet of drywall with a 1-square-inch hole can allow 30 quarts of water per week to pass through by air leakage when the interior is at 70°F and 40% relative humidity. Vapor diffusion through the same sheet moves only about one-third of a quart. This 99-to-1 ratio makes it clear that air sealing is the most effective way to limit moisture entering building assemblies.
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In climates like Zone 4 Marine and Zones 5 through 8, air-driven moisture is a year-round problem. Summer humidity pushes moisture into cool wall cavities. Winter heating allows warm indoor air to escape into colder assemblies. Both conditions can cause condensation, often hidden behind drywall or insulation.
Moisture intrusion at this scale is a leading cause of building envelope failure. According to Vertex Engineering, envelope issues are involved in up to 80 percent of repair-related construction claims, many linked to water damage and mold.
Air Movement vs. Vapor Diffusion: The Real Moisture Risk
Moisture enters a wall assembly in four ways: bulk water, capillary action, vapor diffusion, and air movement. In most residential and light commercial buildings, vapor diffusion and air movement are the most common concerns. Between the two, air movement is by far the dominant path.
Vapor diffusion moves slowly, traveling through materials at a rate that often allows for drying. Air movement travels through gaps, joints, and penetrations. It moves moisture quickly, often deep into the structure. When that humid air meets a cool surface inside a wall or roof cavity, it reaches the dew point and condenses.
Controlling vapor diffusion alone will not prevent these problems. Air sealing stops the larger share of moisture and reduces the chance of hidden condensation that leads to mold or structural decay.
Why the Northeast Faces Higher Moisture Risk
Mixed-humid and coastal climates combine high summer humidity with long, cold winters. These seasonal shifts create pressure differences that drive air both into and out of buildings throughout the year.
In summer, warm, moist air is driven into cooler wall cavities where it can condense. In winter, heated indoor air escapes into cold assemblies, carrying moisture with it. Both situations create favorable conditions for mold growth and material degradation.
When this moisture enters enclosed assemblies, it can become trapped in wall and ceiling cavities, lingering in contact with wood framing, sheathing, or insulation. Some insulation materials are capable of absorbing and holding moisture within their structure, which allows dampness to persist longer. Over time, that hidden retention can create the right conditions for mold growth, decay, and structural damage, often progressing unnoticed until the problem is advanced.
Moisture risk is further increased by the complexity of modern framing, which adds more joints, penetrations, and pathways for air leakage. Without a verified air barrier, these leaks are difficult to find and seal using manual methods alone.
How AeroBarrier Addresses the Problem
The AeroBarrier system uses a nontoxic fog of sealant to automatically find and seal leaks as small as a human hair and as large as half an inch. After drywall is up, we pressurize the house with a reverse blower door and the fog of sealant gets to work. The result is verified airtightness in just a few hours, with no guesswork and no mess.
This process allows for comprehensive sealing without disrupting the construction schedule. By sealing the entire envelope evenly, AeroBarrier ensures that air leakage is reduced across all pathways, not just the ones that are visible or easy to reach.
Performance Results:
Verified airtightness results, typically 0.6 ACH50 or lowerMeets or exceeds IECC 2018 R402.4.1.2 requirements for Zones 4–8 (≤3 ACH50)Reduces the risk of condensation, mold, and callbacksIntegrates into the build process without extending timelines
FAQ: AeroBarrier and Moisture Control in Maritime Climates
Why is air sealing more important than vapor barriers?Because nearly all moisture that enters a wall cavity travels with moving air. Vapor diffusion accounts for only a fraction of the total moisture movement.
Will AeroBarrier help me meet code requirements?Yes. In most Northeast climates, codes require ≤3 ACH50. AeroBarrier typically achieves 0.6 ACH50 or better, verified on-site.
When is AeroBarrier installed?Between rough-in and drywall, so all trades are finished but the structure is still accessible.
Does the process slow down construction?No. Most applications take less than a day.
Is this only for high-performance homes?No. AeroBarrier is used in production housing, custom homes, and affordable housing for durability, comfort, and compliance.
Will homeowners notice a difference?Yes. A tighter envelope reduces drafts, helps control humidity, and improves indoor air quality.
Next Steps for Builders and Contractors
In Northeast maritime climates, air sealing is not just about meeting code. It is about preventing moisture intrusion that leads to mold, callbacks, and costly repairs. AeroBarrier provides a proven way to deliver consistent, measurable results without adding complexity to your build schedule.
Schedule a demonstration, request a project-specific quote, or speak with a building science specialist about integrating AeroBarrier into your process.
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