Although a metal roof can serve your home for many decades, eventually the material will wear out. Replacing the roof is necessary to prevent water damage inside the home, so knowing the signs that a metal roof is at the end of its working life is important. 

1. Extensive Rust and Corrosion

Metal roofing is coated to prevent against rust and corrosion, but over time this coating wears off and then moisture and oxygen do their damage. If caught early, metal roofs can be repainted and coated. This extends the life of the roofing. If the damage has gone on too long and the metal has begun to deteriorate, then replacement of the roofing is the best option. 

2. Dents and Punctures

Storm damage is the cause of most punctures on metal roofing. Severe hail storms and windblown debris can lead to punctures in the roofing panels. Dropped branches from trees are another major cause. In some cases, it may only be necessary to replace the affected panel. If there is extensive denting over the entire roof, though, a full replacement may be desired for aesthetic purposes. 

3. Sheathing Damage 

Beneath the metal roofing panels is the sheathing, which is typically a plywood layer that forms the base and nailing surface for the roof. If water gets beneath the metal panels due to a leak, then the sheathing will begin to rot from the damp. At this point, the only solution is to remove the roof and replace the sheathing. The metal panels are also typically replaced since they are leaking enough to cause sheathing damage. 

4. Fastener Failure

Metal roofs are typically secured with screw-type fasteners. Over time, the fasteners can rust out or the seals around them may fail. If caught early, you can simply replace the fasteners instead of the whole roof. When the damage is allowed to progress, rust may begin to form in the panels around the old fasteners and water may leak under the metal and cause sheathing damage. At this point, full roof replacement becomes necessary.

5. Warped Panels

Older panels may become warped, particularly if DIY repair attempts have led to over-tightened fasteners or if storms have lifted or dented the panels. Warped panels don't lie correctly, which can look bad and increase the chances of water seeping beneath them. The best practice is to replace metal roofing once warping occurs. 

Contact a metal roofing replacement service if you suspect that a new roof is necessary. A roof replacement company can provide additional information.