I am in the process of buying a house that has a roof with improperly installed flashing:

improper flashing

As you can see from the image, the flashing was installed on top of the shingles instead of underneath them. Our inspector said we would probably need a new roof within a couple of years and we can't afford to have it professionally reinstalled right now anyway, so I'd like to at least seal it up until we can replace the whole roof.

My plan right now is to fill the space under the flashing with some roof sealant like this PL S30 10 Black Polyurethane Roof and Flashing Sealant from Loctite.

Is this a reasonable temporary solution to waterproof it until we can have the roof properly replaced?

2 Answers 2


The flashing is called drip-edge. There may be a properly installed course of drip edge underneath. The exposed course of drip edge may be have been to address leak. I would buy matching shingles, then starting from the bottom, install a 'column' on top of the flashing all the way op to the peak, staggered width-wise, and extending past the flashing by 5/8" or mfr directions. Before starting that, however, I'd open up that 30" wide valley and make sure it was properly dealt with (does not look like it to me, at least I would have put a little hip in the valley to give it definite drainage, sealed it off with some ice-n-water shield, flashed over it and held the shingles back from the bottom edge).


Since the flashing is there and will trap water your choice is a good one or a Henery's or Black Jack roofing product will seal the edge so water doesn't get trapped. I would go with the least expensive since they will all last longer than the time your inspector said was left on the life of the roof. Not much water will go to the side but wind can push it under and then it is trapped.From what I see in the photo the roof looks to have quite a few years left.

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