What do you guess the loss of roof life expectancy is on torch over shingles compared to torch over base?
If the cost out wieghs the loss, or a certain customer's profile (about broke) and the customer is aware of the altered application as well as loss of waranty, how can you chalk that up as a poor install?
As long as there is a complete understanding of services rendered, you should be able to sell a fruit loop box as a hampster condo.
I mean hell, if this wasn't true how the hell do roofers stay in biz :D just kidding Grump
Glass just cause the home owner wants it done improperly and understands it is improperly installed doesn't make it a proper installation. Sure your hands are clean of legal liability but that still isn't a proper install.
I really couldn't comment with hard facts but let me ramble out some thoughts floating about in my head. First as we all know shingles experience granular loss throughout their life. Unless the bitumen totally coats the shingle granuals and soaks into the shingle matte, I can't comprehend how anything is holding the mod bit onto the roof except it's own weight.
Sometimes the savings that comes from doing it yourself can be blown away with one mistake.
The information found in this post is not to be considered legal advice. All information should be considered relative, not specific. Never attempt any repairs you are not comfortable with. Always maintain safety! The author of this post takes no responsibility for any losses that occur. Use at your own risk.