How far can water wick up soil?

Even though there's a vapor barrier covering the dirt in my crawlspace, there is still a strong musty smell in there that sometimes migrates into living area. The soil under the vapor barrier is moist but not wet. Since the vapor barrier is semi translucent, I can see condensation on the underside of the vapor barrier at various air pockets around the concrete footings.
Something could be brewing in those air pockets and is released into the crawlspace via gaps between the vapor barrier and the wall or around the posts.
Some contractors suggest installing a french drain in the crawlspace. If I do that, would it keep the top of the soil dry, or would water still wick up the soil to the top? In other words, can water wick up from just below where the french drain is (probably 2 feet deep), and make it to the top of the soil?
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james wrote:

What's the humidity under the house? Where's the water coming from? Is it wetter on one end of the house than the other? Probably easier to divert water around the structure than under it. For a french drain to work you have to have an output port lower than the water level you're trying to achieve. If you have that, you can probably divert around. Otherwise you need a sump pump. Digging holes outside oughta be much easier/cheaper than trying to do it underneath.
I'd see if the city has a hydrologist you can consult.
As for your question, I can't provide a reference, but as I recall, the wicking distance is soil composition dependent and can easily reach 9 feet. That was very surprising to me.
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Trees are a lot more complicated than that. They use a series of essentially check-valves to get water to the top (similar to veins in people's legs). It's not simple capillary action.

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You're wrong (as usual), whatever "i nviens" are.

Shortens the effective column of water, cutting cavitation. There is a "pump". It's called "photosynthesis". Capilliary action is only one of the (smaller) forces going on here. The leaves contribute far more to lifting water than the roots.
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Wrong. There are several forces at work, including capillary action.
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In typed:

What did those contractors say? They've seen it; would know more than those here who can't see it.
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