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This article describes ten steps needed to get into, inspect, clean, and then dry out a building crawl space and keep it dry.
We add advice on how to keep the crawl space dry and clean so that this process doesn't have to be repeated.
This step by step crawl space entry, inspection, cleanout, dryout and keep dry guide explains how to get into or inspect a crawl space even if there is no ready access, how to assess crawl space conditions, how to stop water that is entering the crawl area, how to dry out the space, how to clean up and if necessary disinfect or sanitize the crawl space, and how to keep out crawl space water and moisture in the future.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
How to Dry Out a Problem Crawl Space, Remove Mold, Rodent Debris Unsafe Materials
Damp or wet crawl spaces or basements are often a source of health and structural problems in buildings. Wet areas beneath the occupied space invite mold contamination, insect attack, and structural rot and may also contribute to bacterial hazards.
Keeping these spaces dry and clean is not difficult if we address the steps needed in the right order.
[Click to enlarge any image]
The crawl space shown in our page top photo was in our opinion not a readily accessible area because of flooding. This decision is made by the inspector on the scene, not by anyone else. The crawl space shown at left was tight and so junk-filled it could not be entered either.
Ten Steps to a Clean, Dry, Safe & Sanitary Crawl Space
We break down a thorough crawl space dryout and cleanup process into these steps - presented here in order as a series of crawl space dryout and cleanup and waterproofing articles:
CRAWL SPACE ACCESS: Enter the crawl space. If there is no crawl space access door, make an entry if necessary; if there is no space to get into the crawl space, outside clues might justify making inspection portals through the foundation wall or through an interior floor.
Crawl space entry procedures are discussed
Separately our series of basement dry out, clean up and leak prevention articles begins
at BASEMENT LEAKS, INSPECT FOR where you will find still more details about how to find and stop the sources of water leaks into building basements or crawl areas.
Watch out: if the crawl area has been wet by a sewage spill, backup, or burst waste piping, the area is unsanitary and may be hazardous to enter withouit proper protection. See CRAWL SPACE SEWAGE CLEANUP.
CRAWL SPACE DRY-OUT: details of get rid of crawl space water & high moisture levels; remove crawl space water, moisture, dampness that is already there.
CRAWL SPACE DEBRIS: get rid of crawl space debris. Junk left in the crawl space makes inspection and cleaning difficult and can support mold, rodents, hold moisture, etc.
CRAWL SPACE CLEAN UP: clean or remove mold from crawl space surfaces; remove unsanitary dirt, rodent droppings, dead animals, etc.
CRAWL SPACE SANITIZERS: Cleaning or sanitizing the crawl space surfaces including the floor. When should we use spray disinfectants, sanitizers on crawl space surfaces? What about sealing wood surfaces?
CRAWL SPACE MOISTURE BARRIERS Crawl Space Moisture Control. Crawl space interior measures to keep water out: sump pumps, dehumidifiers, drainage, plastic or poly moisture barriers on the floor and walls.
Also see our other crawl space dryout and safety discussions beginning
at CRAWL SPACE GROUND COVERS where we describe crawl space venting, crawl space poly over dirt, and crawl space heat, to illustrate current best-practices in keeping a crawl space dry.
CRAWL SPACE DEHUMIDIFICATION: how to dehumidify a damp crawl space. Tips for most effective use of a dehumidifier, suggestions for using a fan to improve dehumidification speed & area coverage.
CRAWL SPACE REINSPECTION: Inspect the crawl space periodically to make sure your crawlspace dryout measures have been effective. How often do you need to inspect the area? It depends ... on site conditions and building history.
At least once a year you should look for any new leaks such as a leaky plumbing drain or an outside water entry problem. If you have been having trouble keeping water out of the crawl area, you should check more often until your confidence is restored.
Watch out: for steps 1-7 above, in some conditions, dust containment, negative air, and more protective gear or help from professionals may be needed.
How to Enter, Inspect & Assess Crawl Space Conditions for Water or Other Problems
Hazards in some crawl spaces include breathing moldy or unsanitary air, getting poked by a rusty nail, stirring up a hornets nest, getting shocked or electrocuted by unsafe wiring while crawling over wet ground, crawling through unsanitary water from burst waste piping, kneeling in unsafe pesticide chemicals left by an ignoramus, and the occasional spider, rodent, snake, or even trapped raccoon.
Wear appropriate protective clothing, use a good light, and don't work alone.
Take a thorough look in all areas the crawl space itself for water and dampness and for unsafe or unhealthy conditions such as
Water: puddles, water stains, signs of prior leaks or actual crawl space flooding, as well as odors that indicate mold or dampness
Moldy crawl spaces: start with a careful visual inspection for mold or mold suspect materials. Keep in mind there may be hard to see or even "invisible mold" such as moldy insulation
Wet insulation or inappropriate insulation materials (we don't use fiberglass or other fibrous insulation materials in wet or damp areas)
Rodent or other animal feces or droppings or urine, or smells from dead animals
Unsafe building materials such as falling or loose asbestos pipe insulation, construction debris, rusty nails
 Harriet Burge, Harvard School of Public Health, and EM Laboratory, a private mold and environmental testing lab - email to D.F. August, 2004. Dr. Burge is an educator, writer, and consultant in the field of indoor air quality and mold contamination.
 Product literature and MSDS sheets for the biocides and fungicidal sealants listed in this article.
 US Centers for Disease Control, CDC: www.cdc.gov/ncidod/diseases/hanta/hps/ describes the risks associated with hantavirus.
 International Residential Code, IRC Section R408, Under Floor Space, http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_sec008.htm, retrieved 3/2/2013
See IRC Section M1305.1.4 [PDF] Section M1305.1.4 for access requirements where mechanical equipment is located under floors.
 International Residential Code, IRC Section R406, Foundation Waterproofing and Dampproofing, http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_sec006.htm, retrieved 3/2/2013
Thanks to reader C. Brown for suggesting the need for detail about rapid dryout procedures for a wet crawl space
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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