I’m buying a 30 year old home and of course the crawl space has problems. The sump pump is defective and a large area of the surrounding gravel is wet. The gravel is several inches thick over a barrier which is good, but what is the best way to dry this space out when the gravel is this thick? Fortunately no mold, but you can smell the yucky dampness in the home. The crawl space is not vented.
One idea I found on the web is to place a humidifier in the center of the crawl and have two fans point towards the dehumidifier. Another suggestion was to have a heat vent warm the crawl, but it’s still summer.
It does have a sump pump but that needs to be replaced. I’m not sure there is enough moisture in the crawl space gravel to drain and discharge. So I’m looking for ways to dry it instead. I may start with a dehumidifier, but what do you think about adding a heat source to the crawl?
Assuming it’s not a conditioned crawl space, it does not meet code if it doesn’t have ventilation. I’ve seen houses only about 10 years old with the floor system largely rotted out due to owners keeping their vents shut year round.
You’ve got wet soil and when it dries, the moisture goes into the air above it and it has nowhere to go after that except to get soaked up by the wood.
Tell us a little about the property. Any slope? bottom of a hill? just water table?
I had a crawl space that could get white caps in the water when the wind blew through the vents. We put a linear french drain around two sides of the home and it has been dry since then, even during our 2 recent 100 year storms. Keep the water out, don’t wait for it to get there and then act.
No way one can tell if the vapor retarder is good, through several inches of gravel. One certaily cannot tell whether all joints are lapped 6 inches and taped, and whether the vapor retarder is turned up and taped to all walls and all penetrations such as posts and pipes.
Crawl spaces do not CREATE moisture. It’s coming in from somewhere, and in the absence of vents, it doesn’t take much incoming moisture for it to collect and cause the problems described. A properly dampproofed and ventilated crawl space witha correctly-installed vapor retarder should be bone dry in any climate. If it isn’t, one needs to find the source of the moisture and remedy that. Energy-consuming mechanical devices should not be required at all.