In the picture you can see water intrusion on the bottom layer of siding above the metal flashing. Was the flashing installed incorrectly? It was never sealed with caulk or anything. There is a second story roof above that picture, and that roof doesn't have a gutter. It is also metal so the water drips off the 2nd story and on to this porch roof.

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  • 2
    Put a gutter on the roof above.
    – Ecnerwal
    Jan 31 at 14:26
  • A gutter won't help. There'll be more than enough splash to soak the siding in any substantial rain. It's a matter of letting it dry out readily, which it can't do if it's sitting in a puddle and tight against the metal.
    – isherwood
    Jan 31 at 16:11
  • 2
    It looks like cement board siding. If it was a Hardie brand, they require a 1" gap from any surface, be it roof or sidewalk. I have seen that stuff swell up and turn to mush.
    – Jack
    Jan 31 at 16:19
  • What would you fill the gap with?
    – ian
    Jan 31 at 17:17
  • The gap isn't filled. It has flashing that goes up well behind the siding.
    – KMJ
    Jan 31 at 18:41

2 Answers 2


Siding should always be kept well above horizontal surfaces for exactly this reason. The manufacturer will specifically call this out in their literature. I'm not sure what I'd do now, given the blind nailing strategy we seem to see here. Cutting the siding exposes a raw edge, which doesn't improve the situation much.

Assess the project yourself and decide whether it's worth pulling the wall off or taking other measures to create a gap of 2-4" while maintaining a surface finish on the bottom board.


Assuming that the flashing has a vertical leg tucked behind the siding, tip your circular saw on its side and use the flashing as a guide. Take a couple minutes to experiment with deeper and deeper cutting depths until you get just enough, then back off from there about 1/16" to avoid marring the flashing's vertical leg. Now take a utility knife and pull on the bottom piece as you work down the line to cut the last bit. By pulling on the bottom piece, you'll get constant feedback on the necessary pressure for the knife and minimally damage the flashing.

And the gutters are a good idea, too.

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