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Crew Installing Crawl Space Vapor Barrier

The Stack Effect

The stack effect is the process by which air flows through your home from the bottom to the top. 

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The stack effect, although it seems like a complicated scientific definition when broken down becomes simple and easy to understand the importance it plays in our homes.  

The stack effect is the process by which air flows through your home from the bottom to the top. 

As warm air rises through your house, it eventually escapes through the roof. Building experts estimate even in a highly insulated home, half the air escapes through the roof each hour. 

The Stack Effect Graphic

This air needs to be replaced and a type of suction is created to draw new air in from the lower levels of your home.   

As a result, this air then passes through the home only to escape out the roof again. 

So this means whatever is in your crawl space or basement travels throughout your home. 50 percent of the air you breathe is coming directly from your crawl space or basement.  

If you have high humidity levels, mold, mildew, and odors in the basement or crawl space will all find their way into your main living space.  

The Stack Effect is Harmful 

The stack effect is more than just frustrating, it comes with genuine health risks if your basement or crawl space is a less than desirable area. Here are a few issues to watch out for. 

Allergic Reactions 

Small airborne partials travel with the air as it moves upstairs. This includes everything from dust to mold spores. As they move upstairs, the air quality in those areas goes down, causing many to have allergic reactions.  

Allergic reactions can range from annoying to majorly concerning. A runny nose or cough is possible, but so is coughing and trouble breathing. Regardless of your specific reaction, living in an environment where you are in a constant state of allergic reaction is not good.  

The stack effect image with arrows

High Energy Bills 

As we talked about previously, the humid air is drawn from the basement or crawl space into the main living area. High humidity levels create an uncomfortable living environment and homeowners tend to run their air conditioning units longer to combat the problem. Increased usage, of course, leads to higher energy bills. These sustained high energy bills are reason alone to invest in a foundation solution.  

Controlling the Stack Effect 

The good news, there is a solution. Controlling water and water vapor in your basement or crawl space eliminates harmful air from your home. In a crawl space that means sealing it off from the outside or, encapsulation and for a basement, consider an interior drainage system and sump pump. 

It’s best to act fast as the stack effect can have a detrimental effect on your home and health.

Free No-Obligation Inspection in PA and NJ

The experts at BQ Basements and Concrete provide a free, no-obligation estimate where they will inspect your homes unique situation and offer a customized solution.  

Schedule a free crawl space inspection with one of our trained experts at BQ Basements and Concrete. Our specialists have been helping Philadelphia and New Jersey homeowners for nearly 20 years and understand the area’s unique climate and conditions.  

We offer a wide range of waterproofing services to parts of PA and NJ including Pottstown, Trenton, Levittown, Quakertown, Doylestown, Flemington, Frenchtown, New Hope, Newtown, Bala Cynwyd, Red Hill, and the surrounding area.


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New Jersey

535 Route 38 East, 149E
Cherry Hill, NJ 08002


106 Park Drive
Montgomeryville, PA 18936