How to Ventilate a Crawl Space to Control Moisture


Along with the discussion of ventilating your crawl space, it's also important to consider installing methods for moisture control that will reduce the amount of moisture that needs to be ventilated. Without proper moisture control strategies, crawl spaces can become breeding grounds for mold, rot, bacteria, radon, termiticides. According to the Standard Building Code, there should be one square foot of opening for ventilation for every 150 square feet of crawl space in a building or structure.

Things You'll Need

  • Vapor barrier
  • Duct tape
  • Power drill
  • Reciprocating saw
  • Crawlspace vents
  • Lay out a vapor barrier across the floor of your crawl space, using sheets of asphalt-laminated paper and polyethylene with a perm value of 1 or less. The vapor barrier should at least be 4 to 6 millimeters thick. Cover between two-thirds to three-quarters of the surface area of the ground so that some moisture can circulate throughout the crawl space, which is particularly good for hardwood floors to prevent excessive drying.

  • Run the vapor barrier up the sides of the walls to prevent moisture from seeping in through the foundation. Additionally, you may choose to use a moisture prevention stain or paint formulated for crawl spaces and basements. Use duct tape to secure the vapor barrier to the tops of the walls.

  • Use a power drill to drill a hole through the mortar mixture of your crawl spase wall. Use a reciprocating tool to cut out a rectangle 8 by 16 inches, which is the standard measurement of a foundation vent. The vent should be placed within the top 8 inches of the foundation.

  • Place at least one vent in every corner of the foundation, which will allow for enough air flow to move through the crawl space. If your crawlspace is excessively damp, consider purchasing a ventilation fan that has built in metrics for measuring vapor pressure, turning the fan on or off as needed. Additionally, you may consider installing a dehumidifier for your crawl space. However, it's important to note that you will have to drain the dehumidifier several times a day while it is in use.

Related Searches


  • Photo Credit Jupiterimages/ Images
Promoted By Zergnet



You May Also Like

Related Searches

Check It Out

22 DIY Ways to Update Your Home on a Small Budget

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!