Dampness in crawlspace

[Mike Woolley]

When we moved into this house in Aug./1998, the crawlspace was completely dry. The sump pump is on one side of the crawlspace. That certain area around the sump pump is dry, but as we have more rain, the crawlspace is getting more wet spots. Now, it completely looks wet, except for the area around sump pump. We did have an inspection done on the home, and the inspector found a crack that had been sealed. Do you think this water is because we are in the middle of the rainy season, or should I have this checked out?

[Melissa BeyerParticipant]

Theres probably nothing you can do about it. When the ground outsides really wet from a lot of rain, the ground water table (or level) rises closer to the surface. As it does, the water level under your house also rises, since all this dirt is connected together. Think of what happens if you push the open end of a glass into a sink of water – the water is held out of the opening by the air pressure inside the glass. However, if you were to use a metal can with both ends cut out, and push the tube into the water, the level inside would be the same as it is outside the can. Since your crawl space isnt an airtight dome all the way to the bottom of the foundation, the water level inside it will rise as it does outside. The same forces act on houses with basements (think of a slighly leaky boat in the water), we just try to control the inflow by sealing all openings, and pumping out any seepage. Theres nothing you can do about this, except try to help the crawl space dry out after the water level goes back down by moving some air through it.

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