When Does The Drip Edge Flashing Go Under The Tar Paper And When Does It Go On Top?

Usely,you put the drip edge on the roof sheeting first, however you could put the tar paper on first. You should cut the tar paper even with the sheeting. Your first row of shingles should overlap the dripedge at lest 1" That way water will drip off and run back to the dripedge then drop off the roof.

WBD