Inspector notes cement roof tiles slipping out of place in numerous areas around house both on front and back. Ridge cap tiles not tacked down with mastic of mortar. Cracked/broken tiles noted on both the rake and the surface of the roof. Nail heads are backing out at rake and multiple rakes are uneven and show signs of movement. Roof valleys should be cut and opened to prevent buildup of debris and proper water flow. Additionally these tiles appear to be the older 12" size that is no longer manufactured and difficult to find replacements. Inspector recommends further evaluation by roofing professional. If the same size, style, and color of roof tile cannot be sourced consider roof covering replacement.