Copper roofing is prized for its durability and beautiful patina, but one common issue that can arise over time is fastener back-out. This happens when the nails or screws holding the copper in place gradually loosen and start to protrude. The main causes include thermal expansion and contraction, which copper experiences more than many other materials, causing the metal to move slightly and put pressure on the fasteners. Additionally, improper fastening techniques, such as overdriving nails or using the wrong type of fastener, can contribute to this issue. Regular roof movement, weather conditions like wind and rain, or even roof vibrations can exacerbate the loosening. A simple way to check for back-out is to visually inspect your roof for nails or screws that look raised or are shifting up and down when gently pushed. Keep in mind to do these checks when it’s dry and safe, preferably on a ladder with proper fall precautions.
If you notice back-out during your inspection, small, safe DIY fixes include gently pushing the nails or screws back into place or replacing poorly positioned fasteners with copper-compatible, corrosion-resistant ones designed for roofing use. Avoid hammering or tightening fasteners too much—this can damage the copper or strip the holes, weakening the hold. When you’re unsure or the problem covers a larger area, it’s best to call a professional roofer knowledgeable about copper roofing to assess the situation. A good contractor should be asked if they use stainless steel or copper fasteners specifically designed for copper roofing and what methods they use to allow for metal expansion without compromising the roof’s integrity. Also, ask if their work affects your copper roof warranty, as improper repairs can sometimes void coverage.