Dehumidifiers can serve as effective waterproofing measures in your crawl space. Whether or not a dehumidifier can help you solve your crawl space problem, however, will depend on the extent of damage you’re seeing in your space. Dehumidifiers help pull moisture from the air and can run fairly consistently, as long as you cycle them regularly. If a contractor believes that the extent of your damage can be confined to high levels of humidity and not, for example, mold growths or standing water, dehumidifiers can help protect your space against immediate damage while also preventing a build-up of air pressure that might, later down the line, circulate moist air through the rest of your home.
However, note that dehumidifiers are not fix-all devices. If you’re contending with more significant moisture levels in your crawl space, it may be in your best interest to pair a dehumidifier with another set of waterproofing measures, like a vapor barrier, interior drainage system, and a sump pump. This way, the multiple waterproofing measures can support one another as they draw unwanted moisture out of your space.