If you have positive drainage topographically away from that space, then the
problem lies in both the moisture retentive qualities of the below deck
soil, as well as the inability of the surrounding soil to translocate the
water away below ground. Many different possibilities exist for why exactly
that's happening, but the solution you propose is not a good idea.

Are you familiar with how to identify what types of soil you have? (sandy,
silty, loamy, etc?)


--
David J. Bockman, Fairfax, VA (USDA Hardiness Zone 7)
email:
http://beyondgardening.com/Albums

" wrote in
message oups.com...
I live in NC with clay soil. A problem area for me is under my deck
where the soil NEVER seems to drain. I've removed the mulch installed
by the builder. :-( to try and help to no avail. I don't want the deck
supports to prematurely rot out from underneath us!

Is it possible/adviseable to install a membrane/barrier on top of the
soil to only permit evaporation and no further water uptake?

Could/should I also add crushed rock to assist in draining the water
away from this area?


Rob