What to use under deck to make a shed?

[Raven]

300 bucks but it'll shed the water for ya...at least on the portion of the deck
it covers. ...other wise i don't think its feasible unless your gonna buy like pressure treated plywood to channel the water away from underneath.
thats two expensive methods. otherwise you'd have to attach eyebolts to the plate below the joists to run a series of nylon rope's to support a heavy duty tarp that could channel the water away. you didnt mention "what" your wanting to store underneath your deck.