Donald: The ones I've seen have had brackets with hooks instead of nails. The brackets have a flat surface for nailing to the decking and two nail like hooks sticking out with the ends bent up to hold the shingle through predrilled holes. Almost every asbestos cement shingle roof I see has been damaged by homeowners and other people unfamiliar with the roof walking on the tiles or from fallen tree limbs. As brittle and easily cracked as these tiles are, I'm surprised we don't hear of more people falling off these roofs. btw....All that I have seen have been installed on steeply pitched roofs. If the hips and valleys aren't damaged, they seem to hold up pretty well, despite the moss growth.