Gutter to nail
Dean Johnson of Time Home suggests that gutters be driven “in the rafters and under the tiles so that the nail head is not exposed.” It also suggests that roofing cement be applied around the head of the nail to prevent leaks and for cement around the raised tiles to prevent it from coiling.
Instead use screws
Ron Hazelton calls Ron Hazelton home suggests that to mount the gutters, you can drive a screw in each bracket and in the face plate in the eave.
Gutter experts advise the replacement of gutter nails with screws. Since the channels expand and contract with temperature changes, the nails have a tendency to loosen over time. In the article Channels drop and hang professional Gutter works explains that although a screw will not keep the gutter from expanding and contracting, the screw cannot be removed as easily like a nail.