Many homeowners are unaware of the amount of water that puddles or floods their crawl space after heavy rains. Before many crawlspace inspections, I seem to get the same response, "I've never seen any water standing in the crawl space, only dampness". When I explain to them that I saw pooling and puddling of water or signs of water in their crawlspace, they seem to remember an occasion when it might have had a couple of puddles. Typically, they completely forget about that one time they saw water because they didn't think it was a problem or they only seen puddles on one occasion.
Many homeowners are unable to inspect their crawlspace themselves, so they rely on plumbers, HVAC, Pest Control Operators, contractors, family, and friends to go down there and look for them. Since this might only happen once a year or more, there might not be any standing water down there at that time. To really know if a crawlspace has a water problem, one needs to inspect their crawlspace immediately following a 3" or more rain. Since they can't inspect that soon after a rain, the homeowner is left with an inaccurate assessment of their crawlspace.
The reason a homeowner should inspect their crawlspace immediately after a hard rain is because the water might not puddle or pool very long if they have a porous soil. Water can disguise itself under 6" of pea gravel backfill or sand, so a homeowner needs to pull back the gravel or sand to inspect properly. Water in some crawls might puddle for hours, days, weeks, or even months. It really depends on the soil and the water table.
Regardless of how long the water stands, any water even for a couple of hours is harmful to the environment of the home. The water will typically saturate the entire ground floor even after it recedes back into the ground. The dampness of the soil after the water recedes will try to evaporate into the atmosphere. A vapor barrier is typically installed to block some of the moisture from evaporating, but even a vapor barrier does not block moisture seeping up from the outside perimeter(where the water comes in) or from the seams of the plastic. If a vapor barrier is installed and water pools up under it, the water will run on top of the plastic. When water pools on top of the vapor barrier, then all of the water must evaporate into the structural components of the crawlspace. The evaporation of moisture into the structural components can lead to mold growth and wood decay. See my post on wood rot for more info on the harmful effects of excess moisture in a crawlspace. In the picture above you can start to see the damage done to the beam by the puddles of water.
The only remedy to puddling or pooling water in a crawlspace is a properly installed drainage system and encapsulation system. For more information on installing a drainage system or encapsulation system in your crawlspace, visit our website @ www.americanbasementsolutions.com/crawlspace-repair.html.
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Thanks for reading the rambling thoughts of a crawlspace inspector,
Larry Ralph Jr.