Concerning roof shingles.
I understand that there is some kind of "adhesive," or perhaps just plain
tar, on the undersides
of the normal 3-Tab style.
The nailing in of these provides the major adherence to the wood
underlayment of course, but how important is the
adhesive bonding ? How does it actually function ?
Is this bonding to the wood, or is it to the underneath shingle (only) ?
How many weeks, generally, of hot weather does it takes this bonding to be