For the valley areas of the roof you will be using valley flashing.
Installing flashing on porch roof.
Nail the flashing securely in place using roofing nails.
Flash the corner first if applicable.
If you already have faulty flashing installed you.
Install the underlayment as directed by the manufacturer then set the valley flashing on top of it.
Install the flashing place the flashing between the joint of the house and the roof.
Lay the cut flashing down at the corner.
Measure the length of the porch roof joint to determine how much flashing you will need.
How to install porch roof flashing step 1.
How to flash a porch addition 1.
Before you apply the flashing you ll need to lay down a waterproof membrane.
Prepare the area where you will install the roof flashing.
Cut an angle with tin snips on one side of the flashing piece from an end.