A few years ago I built a deck on the back of the house. No roof was installed but 2 x 6 supports were installed horizontally from the house to the far side of the deck. Now I want to put some shade panels (covering only part of the deck), using poly corrugated panels. I think these should have some slope for rainfall runoff. Not much snow in the NW. Do I need a slope? If so, how can I create it without tearing out the current support joists?

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    A picture would help a lot here. – DA01 Aug 25 '16 at 17:59
  • In the Pacific northwest 1/4" per foot is plenty in most areas. With that said there are some areas that need much more (higher elevations with more snow). If there are trees close the needles or leaves can cause problems with only 1/4" per foot but keeping the area cleared that would work. – Ed Beal Aug 25 '16 at 19:02
  • The right answer depends a lot on how this thing is framed. It may be very simple to lower the beam a few inches, or you may need to modify the rafters. Please provide photos and/or more detail in your question. – isherwood Oct 25 '16 at 19:42

I'm pretty sure you will need a permit and inspection, sorry to say, because you are enclosing overhead. You wont need much slope for rain if your panels run the full length, but if the run is longer than the panels, you'd either need to caulk the overlap or provide more slope. If the 2x6 are paralel with the slope, Cut tapers out of 2x stock and place them on top of the 2x6s, then place 1x2 or 1x3 stringers perpendicular. If the 2x6 are not parallel, rip 2x stock to varying widths to create your chosen slope.

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