One of the most common and inexpensive means of finishing a flat roof rolled asphalt installs over a drip edge flashing that prevents water from getting under the rolled asphalt material around.
Flat roof with sheet flow off edge.
Depending on how the roofs join you may have to cut a slot to work it in far enough.
If it doesn t pull the drip edge out slightly from under the shingles.
The best way is to install the roof drip edge only along the eaves first then place ice and water barrier in the snowbelt or felt paper underlayment over the drip edge.
Make sure the outer edge extends over the gutter.
It should overlap another piece of ice and water barrier laid below all the way down to the roof edge.
Rubber roof repair kit available on amamzon.
It bends around the edge of the roof channeling any moisture that penetrates the shingles away from the roof decking.
Secure the drip edge with roofing cement.
Slip the wide flat flange of the material all the way under the first course of roof shingles as illustrated.
This lets any water that gets on the roof run down the underlayment and over the drip edge.
Metal drip edge flashing is an important element of any roofing edge.