I totally understand the benefit if doing a tear off when replacing a roof. However, if the customer wants to put a second layer on top, my question is does this affect the warranty of the shingle? Also do you still offer a labor warranty?
i could never keep up with the ever changing manufacture warrantys.
so i dont sorry.
the best thing to do is what your comfortable doing.
what you feel good about doing.
cause i can promiss you the h/o will be calling you
long before the manufacture , if somethin goes wrong
I know that GAF/Elk, will carry full warranty on lay-overs, but I never do them. I really don’t know of any manufactures who would not warranty a lay-over. You do have more of a chance for problems when you do them. I would give a 3 year warranty on a lay-over, if the first layer was a strip shingle. 20yr 3 tab. I wouldn’t lay-over a laminate.