Replace Window - Top patch or not to patch roof felt?

[bobbyb]

Im probably overthinking this...

 

So im replacing all the velux windows in my son's room. They are old, and the previous owner painted them, which still annoys me!

 

My son's room is a loft conversion and we are partially rebuilding it, which means we dont have to install the same size windows. We could go larger or smaller/taller/wider, and adjust the stud framework that supports the current windows (in this case, its not structural)

 

My question is about the felt - when I remove the old window, obviously there will be a window-sized hole in the felt. Does it make sense to patch/repair this before we recut it for a new (potentualy different sized) window? 

 

cheers all