Small ceiling stain only after wind-driven rain

I am chasing a small ceiling stain near an exterior wall. The strange part is that it does not show up during ordinary rain. It appears after storms where the wind is pushing rain toward that side of the house.

There is no plumbing in that section. The roof above looks normal from the ground, although obviously that does not prove much. The stain is also a little inward from the exterior wall, so I know the visible spot may not be directly below the entry point.

My suspicion is flashing, a roof/wall intersection, or water getting behind siding higher up and then traveling along framing before it becomes visible inside.

I can inspect the attic safely from inside. After the last storm I saw one area of slightly darker wood but nothing dripping, and by the time I looked everything was already drying. I am thinking the useful move is to check during or immediately after the next wind-driven rain with a flashlight and maybe mark any damp area so I can trace upward.

I am not going onto a wet roof, and if the source is not visible from the attic I will call someone rather than start dismantling exterior materials.

Are there particular signs worth looking for in the attic—water tracks on nails, staining direction, wet insulation, something around penetrations—that can help distinguish a roof leak from water entering through the wall?

The stain itself is small and has not grown between storms, so I am not treating this as an emergency. I do want to catch the source before repeated wetting turns a minor flashing problem into damaged insulation or framing.

  • leaks
  • roof
  • water-damage
54

7 replies · Sort: Best

Best
  1. AB
    abilio_95
    6 points

    3 replies

    In the attic, I’d look for the path rather than the stain itself. Water likes to travel along framing and nails before it shows up where you...

    63 replies

    In the attic, I’d look for the path rather than the stain itself. Water likes to travel along framing and nails before it shows up where you notice it.

    6
    1. MK
      megha96
      0 points

      And sometimes the darkest wood is not the leak point, just the stop along the way. People get fooled by that a lot.

      0

        So if the stain is inward from the wall, that doesn’t mean the source is inward too? I’m trying to picture how far water can move before it...

    2. GG
      giri_gole
      4 points

      0 replies

      Marking damp areas after the next storm is a good plan. If you can compare one wet period to the next, the pattern usually becomes clearer t...

      4

      Marking damp areas after the next storm is a good plan. If you can compare one wet period to the next, the pattern usually becomes clearer than it looks in a dry attic.

      4
    3. NV
      quietorbit3
      4 points

      1 reply

      Wind-driven rain points me toward flashing or a siding joint too. The fact that it only shows up in those storms makes me less suspicious of...

      41 reply

      Wind-driven rain points me toward flashing or a siding joint too. The fact that it only shows up in those storms makes me less suspicious of a plain roof leak.

      4
      1. JF
        james.friedmanOP
        1 point

        Same. I’d look for where water could be pushed sideways, not just straight down.

        1