Crawlspace Vapor Barriers
Believe it or not, your home’s crawlspace has an impact on both energy efficiency and your home’s air quality. This is why we usually recommend installing a crawlspace vapor barrier and air-sealing the entire space.
How Vapor Barriers Work
When you open a crawlspace hatch, do you notice a stench or moisture? A correctly installed vapor barrier can solve these problems effectively.
For both wet and dry crawlspaces, we seal the earth from the crawlspace air with a 15-20 mil vapor barrier. For comparison, a Heavy Duty Hefty bag is just 3 mil. This barrier prevents moisture in the ground from entering the crawlspace air and, eventually, your home. Even dirt that feels dry allows significant water vapor to pass through. We mechanically attach the vapor barrier to the foundation walls and seal it with a water-based sealant to keep moist air out.
If there’s a significant bulk of moisture in the crawlspace, such as standing water, adding a French drain is often the best solution. However, we can also install drainage under the home with a sump pump below the vapor barrier to manage water effectively.
How Crawlspace Sealing Works
After the vapor barrier is in place, we can close off your crawlspace vents. These vents are designed to vent the moist air from the dirt out of the crawlspace. With the vapor barrier preventing moisture from the dirt, we can safely close these vents. Next, we install a small exhaust fan, set to maintain the minimum ventilation needed for the space. This fan typically uses under 10 watts and is virtually silent.
Crawlspace sealing greatly reduces the amount of infiltrated air from the crawlspace to the home. By minimizing this infiltration, you reduce heating and cooling loads. If we can place your HVAC system’s ducts in a sealed crawlspace, it’s a huge bonus. This area becomes almost as conditioned as the living space above, reducing conductive losses from the ducts. A sealed crawlspace also improves the air quality of your home by reducing infiltration from the dirty crawlspace.
There’s no better place than a mild-temperature, clean, vapor-barrier lined crawlspace. We love working in sealed and conditioned crawlspaces, and you’ll love living above one.
Schedule a Free Assessment
Your comprehensive assessment begins with an in-depth call with one of our home efficiency experts, where you can ask all your questions. During our conversation, we’ll ask about your goals, the current setup of your home comfort system, and any time and budget constraints you might have. If you want to move forward with a home evaluation, we can schedule it during your assessment.
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