Roofing nails are an essential part of the installation of shingles as they help to hold the shingles in place even through intense windstorms. These nails, available in various sizes and shapes, are spaced every few inches along each row of shingles to hold them in place. The nails can go through the decking or sheathing, which is the base layer of plywood along the top of the house, and right into the open space of your attic.
In the ideal situation, the contractor places nails right into the trusses and rafters, which are the crisscross components of plywood that help to form the roof structure. They can also use shorter nails on other areas where those trusses don’t exist. Those smaller nails are less likely to protrude into the attic. In all situations, it’s not necessarily a bad thing that the nails are exposed, as it doesn’t create any higher risk of roof leaks. That is unless there’s damage to the wood surrounding the nails. For example, if the decking is rotting, the nail is likely to further pull apart the damaged wood, creating bigger gaps and holes and increasing the risk of leaks. Most often, your roofing contractor will not install new roofing over a bad deck, though.
If there is damage, chances are good the roof needs to be repaired (and that’s more than just the result of the nails poking through in most cases).