Sorry ! ... my first posting... and put it in the wrong area below a number of messages ago .
Wow ! That’s a mess alright…
could you let us know more about the roof , the slope, existing ventilation , and approximately how warm it was when the shingles were installed, and any idea how long the old shingles lasted?
I see in the pics where it looks like they had a 2/6 nailed to the roof to work with …as the faint line across the shingles kinda indicates .
I have seen shingles that were stored for many years, then installed, deteriorated noticeably faster than others .
It also looks like at the bottom edge of some of the shingles are damaged by exesive work boot type traffic … as using shoes other than soft soles really mess up a roof quickly.
I’ve seen Crazy Roofers installing late winter , with frost every morning and I bit of snow too if memory serves. I’ll have to take a look at that roof now , come to think about it , I would think the shingles would have a tendency to crack or shatter in the cold… You would not catch me on a roof with any noticeable frost … gravity works to fast …