How do you keep a 2nd story deck from leaking onto the enclosed porch below?

This is a loaded question and one you have asked before, and not, I judge with any good suggestions and I probably know why. You can't really stop the deck run off onto the (I suppose a roofed porch below), and I assume you have a trough system on the porch below. But isn't that half the pleasure sitting in a porch and having the rain patter. I think so. Unless you have structural damage pending, or you know of, is that what you mean ?

Is your deck flooring made from 2X6 deck boards? If so... the space between the boards is necessary to accommodate the seasonal expansion and contraction of the wood. You can install solid 4X8 sub-flooring on top of the deck boards if you want to seal them.

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