Hi, I will be replacing several asbestoes tiles that have broken /
fallen. I will not be able to remove the previous nails nor get the
new nail under the tile above it, is there a way? Should I do
anything special with the exposed nail (silicon) to prevent water
seepage under it? Some of these tiles will be continually exposed to
weather and some sheltered. I am clueless about this so any
suggestions short of some one else doing the work will be appreciated.

Thanks in advance,
Bill