Open Crawl Space Vents Cause Moisture Problems

For decades we were told to close our foundation vents in winter to prevent plumbing pipes from freezing. We were also told to open our foundation vents in the summer time to increase the air flow in the crawl space. Today, the State of North Carolina recommends that your foundation vents be shut year round. In some counties builders are no longer required to install foundation vents.

Open vents in your foundation create moisture issues that lead to musty odors, mold growth, and damage to insulation in the crawl space. When you turn on your air conditioner in the summertime, it changes the air pressure under your home. Warm humid air enters your crawl space through the foundation vents. This humid air starts to condensate on HVAC ducts and trunk lines under your home. The warm air evaporates this moisture and it collects in your insulation and in your floor joists. You do not realize the problem under insulation starts stringing down and mold starts growing on all the wood members under the home. Best practice, as recommended by building scientists is to close your crawl space vents year round.

Crawl Space Mold

Fungus and mold on your floor joists are a dangerous situation. Spores are released polluting air quality.


Properly installed insulation in your crawl space is a critical part of your homes overall building envelope.


You can expect to money on your home’s annual power bills after your crawlspace is insulated and dry.

Contact us directly at (919) 924-7600

Request an Inspection

Did You Know?

Crawl space mold affects the indoor air quality of your home.


2017-03-19T00:59:05+00:00 Crawl Spaces|