Fall – Closing Your Crawl Space Vents

Crawl spaces under your house give a number of benefits. They allow air to circulate under the floor to prevent moisture from building up underneath. When too much moisture is present on the floor joists, rot and mildew can form. In addition, crawl spaces provide access under the house to fix a multitude of other problems such as leaking pipes.

Yet during the fall and winter, crawl spaces unfortunately allow cold air to blow around under the house. If you have pipes located under the floorboards, these pipes can freeze and create plumbing nightmares. Crawl spaces may also allow animals to take shelter underneath to stay warm. It is advisable to close off the vents during the fall and winter and reopen them in the spring and summer.

Yet what if the vents have no covers or flaps? Some vents merely have the screening, while others may be open due to a fallen screen, broken window cover or rusted vent flaps. To block off the vent, you can purchase foam board and cut it to the size of the opening. You can also purchase foam blocks used for outdoor construction. Place the foam into the vent frame. To hold it in place, hammer in a nail or screw at an angle on either side so the foam can’t be removed or fall out on its own.

When summer arrives, you can simply remove the foam to allow air to circulate underneath the house. Always check the amount of present moisture, as you may see it beaded on the wood or dripping down into the soil. If you have dirt as the flooring of your crawl space, consider laying out 6-millimeter plastic. The plastic will prevent the moisture in the soil from rising up and into the floor joists, reducing the likelihood of rot and mold. When the warmer spring weather comes to your area, repair the old screen vent flaps and covers so they are in working condition.

Some people consider closing the vents permanently so no air can get underneath the house and create a moisture problem no matter the season. If you have ductwork or pipes underneath the house, you will need some way to reach them without tearing up the floorboards in your home. So take this circumstance into consideration if you are wondering if you should permanently close all the crawl space vents around your house.

Get your home ready for the cooler fall and winter weather by closing the outdoor vents. You will save more money on your heating bills as the cold air won’t rise up through the floor or freeze your water pipes.