Concrete tile fastener back-out happens when the nails or screws holding the tiles in place gradually loosen and begin to come out of the roof deck. This can be caused by a variety of factors such as strong winds, thermal expansion and contraction of the concrete tiles, improper fastening techniques, or using the wrong fasteners for the tile and roof deck type. Over time, the vibration and movement caused by wind or temperature changes can cause fasteners to back out, which compromises the stability of the tiles and can lead to leaks or broken tiles if left unchecked. It’s important to understand that concrete tiles are heavy, so any fastener failure puts significant stress on the remaining nails or screws.
To check for fastener back-out safely from a ladder, look for tiles that appear loose or raised, especially near the edges or ridges of the roof. You can gently press down on tiles (with care to avoid cracking them) to see if they shift or move easily. Listen for rattling sounds as well, which might indicate loose fasteners. For warranty purposes, damage caused by incorrect fastening may not be covered, so it’s important to document anything unusual before calling a professional. When consulting a roofer, ask if they use corrosion-resistant fasteners sized specifically for your tile and deck material, and whether they recommend a complete fastener inspection or replacement. A skilled contractor will inspect and replace loose fasteners and may use special locking caps or clips designed for concrete tile roofs to help secure tiles against back-out in the future.