how to fix small leak in roof - likely from flashing under dormer

[CptCool]

Over memorial day weekend my tenants said they had about a half gallon of water drip through their ceiling. In the pictures below, the water is coming in the corner of the house in the bottom right corner. I was out of town and didn't see anything myself, but there was some heavy wind/rain when it happened. We've had light rain since then and haven't had more leaks.

I just got back and took a look on the roof and saw no popped nails, loose/missing shingles, etc near where the drip actually came in. However, as seen in the picture below, there was some flashing curled up with nails that had rusted and popped out of place. This is under a dormer window, so it is mostly protected with an overhanging roof. The wind likely just blew some water sideways across the roof and under the flashing.

The roof itself isn't in great shape, but I was still hoping to get a few more years out of it. This would be my first roof repair and I'm a bit lost on how to fix this leak. Should I get new flashing and simply slide it under the existing flashing? Should I use nails or screws? Should I just re-use the existing flashing and get some slightly wider nails and slap a whole ton of roof cement pretty much everywhere?

I've got some conflicting info on how to go about the repair and it seems simple but I'm worried about screwing it up as it is the tenants house so I wouldn't know immediately if it was just a small leak and I would also prefer not to bother them over and over while i attempt multiple fixes. Any help would be appreciated!







EDIT: Couldn't figure out how to attach the image properly, so see them here: https://imgur.com/a/p9kxzMl

[Jon Bon]

Find leaks is way hard.

So a short story.

I had a small roof leak, it was rather steep so I did not want to go up there. I called my guy he showed up, monkeyed his way up the roof and patched the section in about 20 seconds. The cost was $200 bucks or so. Money well spent why? Because the hole in the roof was nowhere near where it was coming into the house. Leaks can travel a very long way. So you can be banging your head against the wall trying to find where it is coming from.

Your paying for the expertise, not the repair itself.

Call someone you trust.

[J Boogie]

My guess is that the shed dormer wasn't flashed properly all the way up. Looks kind of like whatever flashing was used stopped halfway up.

[lthenderson]

I too would say that the bent base flashing you are referring to isn't the problem. It may be as J. Boogie said since the step flashing on the dormer doesn't appear to go all the way up, or most likely, it is at the intersection of that flashing and the bent base flashing. Water running down along the edge of the dormer can funnel into a gap between that flashing and the bent bent flashing. A lot of times, roofers take the easy way out and join those two pieces of flashing with a sealant that can dry up, crack, separate, etc. over time. For proper flashing, the base flashing is installed first and then your first piece of step flashing is installed so that it extends OVER the base flashing. In your pictures, it appears to stop short which means the intersection of where the two faces of your dormer meet and the roof surface, is probably dependent on caulking that has failed.

I have attached a video that shows how to properly do this intersection.

https://www.youtube.com/watch?v=VDTZKST5PNA

[Sibley]

I have a similar leak. I put a bucket underneath it, because I've tried to patch it several times, it keeps coming back, and I don't feel like bothering again. If the bucket works, great. I'd rather not replace the roof this year.

[slackmax]

I have a small leak into my ground floor from a french door above it.

I've tried for 2 years to find the source of the leak. Only leaks when the wind is blowing on the north side of the house during rain. Spraying water on the north side will not make it leak though.

I'm starting to wonder if the roof is leaking and the water making its way down the siding into the french door.   

[former player]

I have a small leak into my ground floor from a french door above it.

I've tried for 2 years to find the source of the leak. Only leaks when the wind is blowing on the north side of the house during rain. Spraying water on the north side will not make it leak though.

I'm starting to wonder if the roof is leaking and the water making its way down the siding into the french door.   

I struggled for a long time to find a leak below a window: turns out the seals had failed on the double glazed unit and water was getting in and then leaking out of the bottom: it didn't show up as condensation between the glass panes because the water inside the unit was leaking out of the bottom....