Is there a standard in how new felt should be installed under a valley flashing on a tile roof?
My understanding is the existing valley flashing needs to be removed, new felt needs to be installed on both sides in a weaved pattern before the valley flashing is put back.
Is that pretty much the only way to properly install new felt on a existing file roof?
I have also heard argument to leave the existing felt alone, install new felt on top and leave it lying on top of the flashing. In this case, the flashing does not need to be removed, and new felt can be installed on either side independently.
Does this technique make sense? Is it acceptable?