Replacement or re-roofing is usually required on shingles that are over the years old simply because of the age of the roofing materials. Consideration should be given to the underlayment, ventilation and insulation because together these elements play an essential role in preventing heat and moisture build-up from damaging the roofing structure and materials. You should also give careful thought to choosing an effective gutter guard system that protects gutters from clogging. A reputable roofer will make sure that all...