Fix a gap in flashing

Question

We had a sun room added to the first floor. A few years later I noticed signs of a small water leakage causing bubbling in plaster on the inside beam in the house where the sun room meets the house.

I looked up, way up... and noticed a gap between the flashing and the siding where the tar paper is exposed to the elements. This would be a likely cause of the water leak as we do sometimes get driving rain that could come in.

The gap exposing the tar paper is twelve feet long and about two inches high.

What can I seal this with that will stand up to strong sun exposure and water?

Answer 1

Perhaps slide a thin piece of aluminum flashing up under the aluminum siding so that it overlaps the lower flashing. Attach it with a few nails just under the lip of the siding and spray the nail heads with the spray rubber stuff or put a dab of caulk over them.