Strip off the first 3 layers or more of shingles going up the roof the length of the work area.
How to extend flat roof overhang.
Slide the flashing in and line it up so that the bent angle runs parallel to the overhang.
Remove the drip edge and the facia trim.
Set up scaffolding.
This video will.
You will likely have a budget for the project and in this case learning that a flat roof generally costs less than a pitched roof will be good news.
Flat roof extension cost.
Get up on your roof or scaffolding.
Follow safe working procedure falling.
You need to get up to the area that you are going to extend.
Slide your first sheet of flashing under the first layer of shingles.
Take the longer flat side of the flashing and gently slide it in between the first row of shingles and the roof.
This is because a flat roof requires less structural engineering and can utilize less expensive materials than the pitched variety.