Basement Crawl Space Ventilation Systems

New Basement Crawl Space Ventilation Systems are Keeping Homes Healthier

By Mark J. Donovan




One of the chief reasons mold and mildew growth in the home has become a major concern is due to the simple fact that homes are built much tighter than years ago. One of the downsides of a tightly built home is that higher moisture levels are observed in the home. Higher moisture levels within the home can frequently lead to mold and mildew growth. Basement crawl spaces are one of the major contributors for creating moisture in the home.

Besides causing mold and mildew, unventilated crawl spaces can cause outright rot and decay of the home’s framing structure.

Consequently it is important to ventilate the basement crawl space to eliminate the high moisture levels in the crawl space.

Yesterday’s Basement Crawl Space Ventilation Systems

In the past, crawl space systems were manual and typically consisted of vents that could be opened or closed depending upon the time of the year and outside humidity levels. These were a pain to maintain and use, as it meant crawling into the crawl space and opening or closing the vents depending upon the time of year and humidity levels.

As a result, crawl spaces were never effectively ventilated.

Today’s Basement Crawl Space Ventilation Systems

Today, with new technology there are crawl space ventilation systems that can monitor both the crawl space and outdoor temperature and humidity levels.

When outside conditions are right for ventilating the humid crawl space, the vents are automatically opened and a fan in the ventilation system pulls in the dryer outside air and/or pushes out the humid crawl space air.

Normally with a crawl space ventilation system there are at least two, and possibly several, crawl space ventilation vents/fans. Some may act as exhaust units and others as intakes.

 Basement Remodeling Bid Sheet

As a complete crawl space ventilation system they will work together to ensure that the crawl space has sufficient airflow and that the humidity level is maintained to a low level. The only issue with these types of systems is that the crawl space may need to be heated if there is plumbing within them.

For example, in colder months these type of crawl space ventilation systems suck in cold, dry air. This cold air could cause the freezing of pipes. As a result, pipes may need to be insulated and/or the crawl space partially heated.

Other Basement Crawl Space Ventilation Tips

Another way to suppress moisture levels in a basement crawl space is to install polyethylene (plastic) down on the crawl space floor. This is particularly important if the crawl space has an earthen floor.

Crawl space venting

By laying a sheet of polyethylene plastic on the floor of the basement crawl space you can dramatically reduce the amount of moist air in the crawl space.


For more help on Basement Additions, see HomeAdditionPlus.com’s Basement Remodeling Bid sheet. The Basement Remodeling Bid Sheet will help ensure that your hire the right contractor so that your basement remodeling project is done correctly and you get the project finished on time and budget.

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