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  • Writer's pictureCody Ferrell

Crawl Space Ventilation: To Seal or Not to Seal, That is The Question

A vented crawlspace is a traditional way of constructing residential properties. It has a built-up foundation that is above grade and the structure (floors, walls) sit atop leaving a space between the dirt and floor of the home. “Venting” this space is intended to allow air to flow through to prevent the build-up of moisture and stale air and is an acceptable building practice according to modern building standards.

In certain drier climate zones this may be an “okay” means of construction due to a lack of humidity, but in Tennessee we have extremely high humidity for months on end that would cause the crawlspace to be a breeding ground for mold given the right environmental conditions.

This leads us to the question. Do I need to seal my vented crawlspace?

The answer is not that simple.

Many homes with vented crawlspaces perform sufficiently, allowing air to flow freely through it, preventing the buildup of excess moisture and humidity, and have limited moisture intrusion from surrounding elements. The wood framing is likely in good shape, with little to no mold present. If this is the case, it is hard to tell someone to spend the money to encapsulate their crawlspace, but environments can change.

More often than not, vented crawlspaces do not vent properly and usually have multiple moisture intrusion issues. This could be from blocked or too few vents, poor layout, HVAC ductwork blocking airflow, poorly installed vapor barrier and moisture intrusion issues surrounding the structure, like downspouts terminating at the foundation wall, or the slope of the yard is directed towards the home. This crawlspace likely has some compromised wood framing and varying species of mold growing throughout.

Sometimes issues are only present in specific areas of the crawlspace, areas with pockets of stagnant air, areas that are barely accessible or blocked by ductwork, or areas that have bulk water issues. This may not be a systemic issue and may be repaired by minor alterations to the layout or moisture management systems.

Each crawlspace is different because each house is different and is subject to different environmental conditions. We evaluate each crawlspace and do not prescribe a blanket repair for all, we will help you decide what repairs are needed and give step by step recommendations to improve your home’s condition.

If you’re curious as to what’s going on in your crawlspace give us a call and we’ll come and give you a full assessment of its condition.

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