Obviously had never felted a roof before. First, used a thin underfelt instead of a thicker mineral-finish felt (which was taken off the roof for renewal). Second, did not know how to form a drip edge, even nailing timber where water runs off the roof, making the timber rot.. Underfelt has since buckled and pulled away from the clout nails, requiring repairs within a year.
Might be good at gardening, but no knowledge of roofing.
Sorry I chose them off the internet for my son. Very expensive.