The metal rain diverter strip above our back patio door completely rusted out over the winter, meaning all the heavy roof runoff was cascading straight down onto the door frame instead of shooting out into the grass. Leaving it like that was slowly rotting the wood trim and leaking water into the threshold every time a storm hit. I picked up a basic aluminum flashing shield at the store today, figuring I’d just slide it under the shingles and nail it down in five minutes flat. What a total joke.
The main headache was trying to pry up the bottom layer of shingles to get the old metal strip loose. The original roofing tar had baked under the sun for years, essentially gluing the shingles completely flat to the plywood roof deck. I spent forty minutes balanced on a shaky extension ladder, aggressively wedging a flat putty knife under the brittle tabs while trying not to tear the asphalt material right in half. Every time the wind picked up, the ladder would sway slightly, which completely panicked me.
Once the old rusted guard finally broke free, sliding the new aluminum flashing piece into the tight gap was an absolute puzzle. The roofing nails from the row above were blocking the track, so the long metal sheet kept buckling and bending out of shape every time I tried to force it under the shingles. I had to get a flat crowbar and blindly hammer down three hidden nail heads beneath the tiles just to create enough clearance for the flashing to slide into place.
The new aluminum shield is finally tucked deep under the shingle line now and securely fastened down with heavy duty roofing screws. The pitch angle slopes perfectly toward the side gutter line and the metal sits completely flat against the eave without lifting the shingles. The patio doorway is fully protected from the roof runoff now.