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We just found this dip in our roof that it causing rain water to leak through the wood directly under it. (It covers an open patio, not interior living space.) We'd like to make the repair ourselves instead of hiring a roofer, but I'm not sure where to start. The roof has asphalt architectural shingles and we live in the northeastern U.S. where we get a lot of rain, snow, and wind. Basically, our roof takes a beating so we need to make sure the repair is sound and will hold up in nasty weather.

  • Can you lift up the bottom shingles to see what's underneath? My bet is it's the gutters, but there's a myriad of reasons for this.
    – Machavity
    Apr 20, 2017 at 3:18
  • My recommendation is to use your neighbor's roofer. If you look closely at his roof you'll notice his gutter supports (spikes) are installed at about 24" oc. Yours are about 36" oc. In an area with, "lots of rain, snow and wind," this is important. Plus, I'll bet that roofer won't cut corners when he fixes your roof.
    – Lee Sam
    Apr 20, 2017 at 3:45
  • Our neighbor's roofer put holes in the roof to install the gutters which even if know is a big no-no. Any holes in the roof is an invitation for a leak. Regardless, that house is occupied by tenants and we do not know the owner. Apr 21, 2017 at 1:37

1 Answer 1


This problem is likely caused by one of these things:

  1. The wood roof sheathing under the sag area is rotted away eliminating the support for the shingles.
  2. There is a gap between the sheathing edge and the rain gutter with no support for the shingles. Over time with heat and freezing cycles and winter ice build up the shingles has just sagged into the gap.
  3. The rain gutter was installed too high on the rafter end fascia and it pushed up the tails on the lower course of shingles.

The fix needed to take care of the problem will require detailed analysis to determine the exact cause of the dished shingles. Once that is understood you can proceed with the proper fix.

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