How do I get a Dry Crawl Space?

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  • Written By: Synthia L. Rose
  • Edited By: Lauren Fritsky
  • Last Modified Date: 14 August 2019
  • Copyright Protected:
    Conjecture Corporation
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A dry crawl space can be created and maintained through proper ventilation, vapor barriers, and the use of dehumidifiers. Adding foundation vents will increase air circulation in a crawl space that has been overtaken with humidity or standing water, thereby drying out the atmosphere. Strategic vent location and vent sizes can be recommended by a professional plumber after an inspection. Small fans can also create ventilation in a crawl space. Such fans do not have to be installed permanently, but can be placed in a crawl space sporadically to handle moisture issues.

A dehumidifier can prevent mold issues and decrease condensation. Many hardware stores sell portable dehumidifiers. These machines work by collecting water from the air through the use of small internal fans and refrigerated coils.

Vapor barriers are sheets of plastic or foil that can be stretched over the ceilings, floors, and walls of crawl spaces to encourage a dry crawl space. These barriers usually prevent moisture from penetrating the foundation of a home and causing mildew. Insulating water pipes, particularly cold water pipes passing through the crawl space, with fiberglass wraps, duct wrap, or foam can also create a dry crawl space. These protective liners, however, will not dry out the air if excessive moisture has already accumulated.


If there is standing water, a wet vacuum or water pump may be needed to create a dry crawl space. These electric pumps will work in emergencies by transferring water into a large bucket or outdoors. For long term, however, installing one or two sump pumps may be necessary to keep a dry crawl space. These sump pumps will collect rainwater and ground water under a home, reducing seepage and flooding.

Once pumps, vacuums, ventilation and barriers have reduced moisture, homeowners should consider controlling indoor temperature as a strategy to create a dry crawl space. Many homes benefit from properly-adjusted thermostats and humidity controls. The ideal temperature for most homes is typically between 67 degrees and 73 degrees Fahrenheit (19.4 to 22.7 degrees Celsius). Many heating and ventilation professionals recommend that humidity controls be set between 30 percent and 50 percent humidity. Using appliances like clothes dryers and dishwashers, however, can cause a home’s humidity to wildly fluctuate; fans and dehumidifiers can be used near appliances that spike moisture to maintain the proper humidity range.

Lastly, many ventilation experts advise caulking any air spaces that can allow moist air to penetrate from outside. Plumbing leaks, if not immediately repaired and sealed to prevent moisture accumulation, can ruin plans for a dry crawl space. Grading the lawn so that rainwater and water from sprinklers do not create puddles near exterior walls will also usually help maintain a dry crawl space.



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