Should Vents in Crawl Space Be Open?

Your crawl space vents should always be closed and sealed off from the outside elements. ... First and foremost, open vents allow moisture to enter your crawl space. This creates the perfect environment for mold growth and mildew.

When should crawl space vents be open and closed?

These vents allow outside air to circulate under the floor in summer to prevent the moisture buildup that encourages mildew and rot. In winter, when the air is drier, the vents are closed to reduce the chance that the pipes in the crawl space might freeze.

Should I open crawl space vents in summer?

Building codes generally require working vents in the crawlspace to allow outside air to circulate under the floor in the summer to prevent moisture buildup that, among mildew and mold, encourages wood rot.