Crawlspace maintenance for good air flow
Crawlspaces should be equipped with foundation vents. This is code in most cities of the United States. They should be installed to provide cross ventilation in the crawlspace.
You can keep your crawlspace dry and healthy by paying attention to a few things. Hand excavated french drains should be installed to remove groundwater next to your foundation. In the summer when warm air is drying out the landscape, open the foundation vents and let warm air flow through the crawlspace the entire summer.
Most often foundation vents have flapper doors that can be opened and closed. If permanent foam blocks are used to block the foundation vents, remove them during the summer.
In the late fall, when the cold air takes over, close these foundation vents and stop the cold air from bringing additional moisture into your crawlspace.
Check your crawlspace to determine if your moisture barrier plastice, usually 6 mil. thick, is in place and look for evidence of mud stains on the moisture barrier. If you see mud stains, you are likely getting groundwater in your crawlspace from the winter rains.
Hand excavated french drains, and a compacted splash block around the home would be your best solution to stop the groundwater caused by heavy rains from entering your crawlspace.
Look at your rain drain discharges on the outside of the home that vent your roof water through the downspouts. Make sure they do not show evidence of overflowing next to the foundation. Usually a depression will wash out behind the rain drain discharge and the foundation wall, making a hole.
Look for a drip line on the ground under the edge of the gutter. Are the gutters overflowing? Clean those gutters often to remove groundwater caused by overflows next to your foundation.
Paying attention to these details can benefit your home with healthy air in your crawlspace and therefore in your home, and prevent saturation and leaking into crawlspaces caused by groundwater that comes from heavy rains. Groundwater produced by heavy rain is most often the major cause of a wet crawlspace.